Section — Prümmer, Manuale Theologiae Moralis
§ 4. On the Efficacy of Prayer and Its Conditions
The efficacy of prayer is very great; for it produces three primary effects and several other secondary effects. The three primary effects of prayer are merit, satisfaction, and impetration; while the secondary effects are many: for prayer disposes one for grace, enlightens the intellect, nourishes faith, confirms hope and confidence, inflames charity, increases humility, produces ineffable consolations, fosters the exercise of all the virtues, etc. A few things are to be said concerning each.
349. a) The primary effects.
Prayer is meritorious when it is poured forth as it ought to be by a just man who is a wayfarer.125 For prayer is a good work. Moreover, every good work of a just man who is a wayfarer, proceeding from the root of charity, is meritorious, and indeed de condigno. Such prayer merits an increase of grace and glory. Christ seems to speak of this merit when he says: "But thou when thou shalt pray, enter into thy chamber, and having shut the door, pray to thy Father in secret: and thy Father who seeth in secret will repay thee."126 But although only a man endowed with sanctifying grace can merit de condigno, nevertheless the prayer of a sinner made with actual grace also merits de congruo (in the broad sense) a threefold good, because a) it disposes him for sanctifying grace; b) it obtains temporal goods; c) it accustoms him to good works.127
Prayer is satisfactory; for it has all the conditions required for satisfaction, since it is a good and arduous work proceeding from grace. That prayer is a good work and proceeds from grace (at least if a man is constituted in the state of sanctifying grace) is evident of itself. Daily experience proves that good prayer is an arduous work, since it is not easy to perform a good prayer. Hence the Council of Trent128 places prayer among satisfactory works, and confessors are accustomed to impose certain prayers for sins as a salutary penance or satisfaction.
Prayer is impetratory, and indeed in two ways, namely insofar as it is a good work, and formally insofar as it is prayer. We do not speak of the first impetratory effect, which prayer has in common with all good works. The discussion here will presently concern only the other effect.
125 S. theol. 2, 2, q. 83, a. 15.
126 Matt. 6:6.
127 Cf. St. Thomas, Suppl. q. 14, a. 4.
350. b) The secondary effects.
Prayer enlightens the intellect, according to the words: "Come ye to him, and be enlightened."129 Wherefore St. Thomas always had recourse to prayer whenever he was unable to understand some difficult truth.
Prayer nourishes faith. For faith and prayer foster one another. Firm faith in the omnipotence, goodness, and mercy of God induces a man to pray; and fervent prayer increases faith, both because it increases grace and because it is itself an exercise of faith.
Prayer confirms hope and confidence on account of the salutary effects often gathered from prayer.
Prayer inflames charity. For "as lovers are more inflamed to love by conversation and meeting, so pious men, the more often by making prayers to God they converse, as it were, with him, are impelled with greater joy at each prayer to love and worship him more ardently."130
Prayer increases humility. For one who prays, conscious of his own indigence, approaches God as a beggar.
Prayer produces ineffable consolations. For if conversation with a faithful friend is pleasant, what at last is to be said concerning sweet conversation with God in prayer? Hence Christ admonishes: "Ask, and you shall receive; that your joy may be full."131
Prayer fosters the exercise of all the virtues, according to the saying: "He who knows how to pray rightly truly knows how to live rightly." The intrinsic reason is that by prayer man approaches God. By frequent and true approach to God, man becomes like God; he flees dangerous earthly things; he restrains disordered passions; and at length he is adorned with the crown of all the virtues.
129 Ps. 33:6.
130 Roman Catechism, Part IV, c. 2, q. 7 (8).
131 John 16:24.
351. Proposition. Prayer furnished with the requisite conditions has, from the promise of God, an infallible efficacy for impetrating the things which are asked.
This proposition seems to be of Catholic faith on account of the manifest testimonies of Sacred Scripture: "The prayer of him that humbleth himself shall pierce the clouds; and till it come nigh he will not be comforted; and he will not depart till the Most High behold."132 Christ repeatedly promised the hearing of prayer: "Ask, and it shall be given you; seek, and you shall find; knock, and it shall be opened to you. For every one that asketh receiveth; and he that seeketh findeth; and to him that knocketh it shall be opened."133 "Amen, amen I say to you: if you ask the Father any thing in my name, he will give it you."134 The Holy Fathers also proclaim the efficacy of prayer very frequently. Thus St. Hilary135 says: "It is the doctrine of our hope that God, when prayed to, both has mercy and saves." Tertullian136 writes: "Prayer alone is that which conquers God; ... it washes away sins; repels temptations; extinguishes persecutions; consoles the fainthearted; delights the magnanimous; ... feeds the poor; governs the rich; raises the fallen; supports those falling; sustains those standing." A certain ancient author embraces the efficacy of prayer in this brief and very well-known proposition: "He who knows how to pray rightly truly knows how to live rightly."137 Several Holy Fathers wrote entire treatises on prayer and its efficacy, which you will find enumerated in Migne, Patr. lat. 220 (Indexes), 959-960.
132 Ecclus. 35:21.
133 Matt. 7:7f.
134 John 16:23. Similar passages are found in Matt. 21:22; Mark 11:24; Luke 11:9; John 14:13; Jas. 1:6.
135 Tract. in Ps. 118 (Migne, Patr. lat. 9, 544).
136 De orat. c. 29 (ibid. 1, 1303).
137 Sermon 55 among the spurious sermons of St. Augustine (Migne, ibid. 39, 1849).
352. The conditions required for prayer to be infallibly efficacious are considered: 1. on the part of the object which is asked; 2. on the part of him for whom it is asked; 3. on the part of the one praying.
- On the part of the object which is asked, it is required for the infallible efficacy of prayer that it conduce to eternal salvation.
For if a man were to ask for something harmful to his eternal salvation, then the hearing of such prayer would not be a reward but a punishment. Since temporal and material goods do not always conduce to eternal salvation, but rather lead away from it, a man asking for goods of this kind is not always heard; indeed, a man cannot ask for goods of this kind in prayer except under the condition that they not be obstacles to eternal salvation, as was said above in n. 338 (c).
- On the part of him for whom it is asked, it is necessary that he be disposed to receive the grace asked.
Hence, e.g., someone praying for the eternal salvation of another man is not always heard, namely when that man pertinaciously resists grace. Wherefore the Angelic Doctor posits as a condition of the infallible efficacy of prayer that someone pray for himself and not for another. "That one pray for oneself is posited as a condition of prayer, not indeed as necessary for the effect of meriting, but as necessary for indefectibility in impetrating. For it sometimes happens that prayer made for another does not impetrate, even if it is made piously and perseveringly and concerns things pertaining to salvation, on account of the impediment which is on the part of him for whom one prays, according to the words: 'If Moses and Samuel shall stand before me, my soul is not toward this people.'138 Nevertheless, the prayer will be meritorious for him who prays from charity, according to the words: 'My prayer shall be turned into my bosom';139 that is, although it does not profit them, I nevertheless am not deprived of my reward."140 Therefore, although according to the opinion of St. Thomas (whom Suarez141 and some others contradict) prayer for the eternal salvation of another man is not infallibly efficacious, it is nevertheless often heard; whence St. James admonishes: "Pray one for another, that you may be saved; for the continual prayer of a just man availeth much."142 Such prayer is always a most excellent work of charity and very meritorious for the one praying himself.
138 Jer. 15:1.
139 Ps. 34:13.
140 S. theol. 2, 2, q. 83, a. 7, ad 2.
141 De relig. tr. 4, l. 1, c. 27.
142 Jas. 5:16.
353. 3. On the part of the subject praying, the conditions required for infallible hearing are: a) the state of grace, b) humility, c) confidence, d) perseverance, e) attention.
a) The state of grace is indeed required primarily. For although God sometimes hears the prayers of sinners, as is evident from the examples of the publican, the thief, etc., nevertheless sin often greatly prevents prayers from being heard, since it makes a man an enemy of and hateful to God. On the contrary, a just man is a friend of God, by whom he is loved and from whom he receives many benefits. Hence it is said: "The eyes of the Lord are upon the just: and his ears unto their prayers."143 "If you abide in me, and my words abide in you, you shall ask what you will, and it shall be done unto you."144 "If our heart do not reprehend us, we have confidence toward God: and whatsoever we shall ask, we shall receive of him, because we keep his commandments, and do those things which are pleasing in his sight."145
b) That humility is required for efficacious prayer is evident from the very nature of prayer, since it is an act of religion by which we acknowledge our infirmity and the excellence of God, subjecting ourselves to the majesty of God. The same is evident from Sacred Scripture: God hears the humble publican, but spurns the proud Pharisee. "God resisteth the proud, and giveth grace to the humble."146 Abraham, praying, professed his humility, saying: "I will speak to my Lord, whereas I am dust and ashes."147
c) Firm confidence, which entirely trusts in the promises of Christ and in divine mercy, is likewise necessary for the efficacy of prayer. Hence St. James admonishes: "But let him ask in faith [confidence], nothing wavering. For he that wavereth is like a wave of the sea, which is moved and carried about by the wind. Therefore let not that man think that he shall receive any thing of the Lord."148 St. Paul exhorts: "Let us go therefore with confidence to the throne of grace."149 Wherefore Christ often performed miracles upon seeing the great faith or confidence of those asking, e.g., of the ruler, the Canaanite woman, the woman suffering from an issue of blood, etc.
d) Perseverance is very necessary in prayer. For although God is ready to hear the one praying at once, man himself is not at once sufficiently prepared to receive graces (but by praying perseveringly he becomes better disposed). For thus, by waiting, he perceives his own unworthiness and indigence more vividly; he esteems more highly the grace finally obtained; and after being heard he is more incited to love and thanksgiving. Christ teaches the necessity of perseverance by various parables and miracles. Thus the importunate friend asking for three loaves finally obtains that which he desires;150 the Canaanite woman, not deterred by repeated repulses, finally obtains the miraculous healing of her daughter, etc.151 Similar to perseverance is assiduity or duration in prayer. This assiduity of prayer also is commended, although it is not altogether necessary. Of Christ himself it is said: "He passed the whole night in the prayer of God,"152 i.e., he prayed through the whole night; and: "Being in an agony, he prayed the longer."153 Concerning the duration of prayer, the Angelic Doctor says:154 "It is fitting that prayer last so long as is useful for stirring up the fervor of interior desire. But when it exceeds this measure, so that it cannot continue without weariness, prayer is not to be prolonged further."
143 Ps. 33:16.
144 John 15:7.
145 1 John 3:21f.
146 Jas. 4:6.
147 Gen. 18:27.
148 Jas. 1:6f.
149 Heb. 4:16.
150 Cf. Luke 11:5ff.
151 Cf. Matt. 15:22ff.
152 Luke 6:12.
153 Luke 22:43.
154 S. theol. 2, 2, q. 83, a. 14.
354. e) Attention is the last condition required, and indeed not only for the efficacy of prayer but for its very essence. Attention is twofold: one external, the other internal. Since attention is opposed to distraction, external attention is that which excludes external distraction, namely all those external acts which occupy a man in such a way that the mind is no longer able to attend to the sense of the prayer. Thus, e.g., external attention is lacking if someone during vocal prayer reads a book or paints or performs some other work requiring keen advertence; but external attention is not impeded if someone during vocal prayer takes a walk or performs some other light work not requiring much consideration. External attention can be called attention in the true sense, since by it a man attends lest prayer be disturbed by external occupations. For just as a guard who attends lest wild beasts break into a flowering garden is rightly said to have attention concerning the garden, so likewise one who prays and drives away external occupations has attention concerning prayer. Internal attention excludes internal distraction or the wandering of the mind to things entirely foreign to prayer.
Internal attention is distinguished a) by reason of its object; for it can be directed to three objects,155 namely: 1) to the words of the prayer taken materially, so that those words are pronounced completely and in their order; this attention is called material or superficial; 2) to the sense of the words, and then it is called literal or also intellectual; 3) to the end of prayer, namely to worshipping God himself, or to the mystery for the worship of which the prayer was instituted, etc. This third attention (which is usually called spiritual or mystical) is more perfect than the others; the second is more perfect than the first.
Internal attention is distinguished b) by reason of state into actual, virtual, and habitual. Actual attention is present if someone actually attends to the sense of the words, to the end of prayer, etc. Virtual attention exists when actual attention was previously present and was never revoked, but now is no longer present because of involuntary distractions. Habitual attention is abusively called attention, because in fact it is not true attention but only a certain inclination to attend. A man devoted to prayers has this habitual attention even in his sleep. St. Alphonsus156 and others confess that they do not understand what virtual attention is. And yet the matter can be explained in a sound sense: if someone, after an actual intention and attention possessed at the beginning of prayer, is then involuntarily distracted, the attention previously possessed is not revoked; therefore it perseveres virtually in the moral sense. Certainly, in the physical sense, every distraction, even an involuntary one, destroys attention, just as cold destroys heat; but since involuntary distractions are not human acts and consequently are not even moral, no influence and no change is caused by them in the previously existing and morally persevering moral act. But at the beginning of prayer there was attention. Therefore this attention perseveres in the moral sense, notwithstanding involuntary distractions. But if voluntary distractions should supervene, then certainly the attention to prayer previously possessed is destroyed even in the moral sense, because voluntary attention and voluntary distraction are directly opposed and contrary.
The older authors of the Middle Ages are not accustomed to speak of the distinction between external and internal attention in prayer taken generally. And in fact this distinction is rather superfluous for prayer itself in the genus of morals. For, at least in the genus of morals, there is no difference whether one praying voluntarily distracts his mind by reading, writing, etc., or by deliberately thinking of something else. For in either case the one praying expressly wills to distract his mind from the object of prayer, although he perseveres in uttering the words of the prayer. The means employed for obtaining this end are of themselves indifferent. But since the canonical Hours are prescribed by the Church, which in the external forum cannot judge purely internal acts, the distinction between external and internal attention is of some moment in the recitation of the Divine Office. For the Church can judge and punish a violation of external attention, but not a defect of internal attention.
Concerning attention, two things are certain among all; but one thing is disputed.
It is certain, 1. that at least some attention, whether external or internal, is required for the essence of prayer. And indeed that which is done without any attention is not even a human act. But how can such an act performed without any attention still be called prayer, which proceeds from reason as from its subject, as was proved above in n. 335?
It is certain, 2. that some internal attention also is required for mental prayer, since mental prayer is essentially an act of the mind. Hence he who voluntarily thinks about other matters during meditation no longer meditates.
It is disputed what kind of attention is required for vocal prayer.
155 Ibid., a. 13; St. Alphonsus, Theol. mor. l. 4, n. 177.
156 Gran mezzo della preghiera Part I, c. 3, § 3.
355. Controversy concerning the necessity of internal attention.
Since this question concerning the attention required for prayer is so practical for the recitation of the Divine Office, theologians dispute sharply whether external attention suffices or whether at least some internal attention also is required in order that a cleric reciting the Divine Office satisfy his obligation. Cajetan,157 Dominic Soto,158 Wigandt,159 and especially Concina,160 who, according to the testimony of St. Alphonsus, maintains this opinion at length and with great learning, teach that external attention alone does not suffice; likewise Reiffenstuel,161 Valentia,162 Suarez,163 Peter Ledesma,164 Bartholomew de Medina,165 Billuart,166 who calls it certain, and St. Alphonsus,167 who calls it more common and more probable. On the contrary, Durandus168 seems first to have taught that external attention alone suffices for the essence of prayer and for the recitation of the Divine Office; he was followed by Lugo,169 Silvester Prierias,170 Tamburini,171 Gobat,172 Elbel,173 Noldin,174 and many modern authors. The older authors dispute this matter at great length. Especially St. Alphonsus, Lugo, Billuart, and Concina are to be consulted. Some think, not without reason, that in practice there is not so great a difference between these two opinions when rightly understood. For all require for vocal prayer (and notably for the Divine Office) material attention for pronouncing the words properly. But this material attention is already a certain internal attention. Therefore all require a certain internal attention for vocal prayer. The following things seem to be true concerning the necessity of attention both in private prayer and in the recitation of the Divine Office:
- Without external attention, neither prayer nor a sufficient recitation of the Divine Office can subsist. Thus all teach, as was already said. Wherefore he who, during prayer or the Divine Office, performs other works requiring grave consideration no longer satisfies the obligation of reciting the Divine Office. But what works are of this kind depends not only upon the nature of the work but also upon the disposition of the one praying. For one person more easily than another loses the attention necessary for prayer.
Authors commonly teach, however, that those who during the choral Office perform works necessary for the choir, such as playing the organ, lighting candles, finding antiphons, etc., satisfy the Divine Office if, in the best manner they can, they attend and recite alternate verses of the psalms. The reason is that they labor more than the others for the choral Office, and it would be excessively harsh if, nevertheless, after completing the choral Office, they were bound to repeat the Divine Office privately. Hence for them the common maxim, "The choir supplies," holds if they cannot attend so well to the words of the Office, or even if they are compelled to omit some verses of the psalms.
All voluntary distractions during prayer are more or less sinful. For they violate the reverence due to God. Thus likewise all teach, if perhaps you except Caramuel,175 who thinks that voluntary distractions in prayer are not even a venial sin, provided external attention is preserved.
In order that someone be said not to have satisfied his obligation of reciting the Divine Office because of a defect of internal attention, it is required not only that he have had voluntary distractions, but also that he noticed that he was voluntarily distracted and did nothing to eliminate the distractions. Almost all (even the authors of the first opinion) teach thus. "Therefore, so long as," Cajetan concludes, "it is not clearly established for them that they changed their purpose, or that, while noticing and knowing it, they wandered about other matters, they can believe that they satisfied their obligation."176
No certain argument can be adduced for either the affirmative or the negative opinion from definitions or decrees of the Church. Even Concina himself, who vigorously defends the affirmative opinion, concedes that the decretal Dolentes of Innocent III,177 which is often cited for the affirmative opinion, proves nothing, since it intended nothing other than to restrain the external excesses of certain clerics.
157 Comm. in 2, 2, q. 83, a. 13. But Cajetan's mind is not so clearly established.
158 De iure et iust. l. 10, q. 5, concl. 6.
159 Tribunal confessar. tr. 10, exam. 5, nn. 82 and 83.
160 In Decal. l. 2, diss. 2, c. 9.
161 Theol. mor. tr. 6, dist. 1, n. 43.
162 Comm. in 2, 2, disp. 6, q. 2, punct. 10.
163 De relig. l. 4, c. 26, n. 3.
164 Summa Part II, tr. 9, c. 4, concl. 20.
166 De relig. diss. 2, a. 8, § 8.
167 Theol. mor. l. 4, n. 177.
168 In IV, dist. 15, q. 12.
169 De euchar. disp. 22, n. 25ff.
170 Summa Summ., s.v. "Hora."
171 Decal. l. 4, c. 2, § 1, n. 19. This author, l.c., c. 6, n. 5, says: "Therefore, he who, while hearing Mass from a precept or performing the Divine Office, would voluntarily revolve a philosophical question in his mind, or think about his affairs, provided he had external attention, ... according to the said probable opinion would sufficiently fulfill the precept."
172 Tract. theol. iur. tr. 5, n. 821. The author, however, does not seem always to be consistent with himself.
173 Theol. mor. Part V, conf. 123, n. 404.
174 De praeceptis n. 139.
175 In Theol. fund. n. 442 the author writes: "I am a man more frail than you yourself, endowed with an acute and fiery disposition. In one moment I turn toward the heavens, in another I pass to things below. No fly is moved in the oratory which is not an impediment to me; ... I do not avoid distractions, involuntary ones a thousand times, sometimes even voluntary ones; and nevertheless I am troubled by no scruple, ... because I prudently suppose that I am not bound to internal action; that to possess it is good, and to lack it is not even a light fault." But that voluntary distractions are not even a light fault is certainly a heap of laxity.
176 In St. Alphonsus, Theol. mor. l. 4, n. 177.
177 c. 9, X 3, 41. Concina's explanation of this decretal is worthy of being read.
356. 5. Since the opinion denying the necessity of internal attention is certainly extrinsically probable on account of the great number of authors who maintain it, no one can be accused of not having satisfied the ecclesiastical obligation of reciting the Divine Office, or of being bound to restore benefice revenues,178 provided that a) he observed external attention and b) he had the intention of satisfying. For it is not certain that the Church wished to impose in the recitation of the Hours anything other than external attention. For the recitation of the Divine Office with the exclusion of external distraction and with the inclusion of the intention of satisfying the ecclesiastical precept seems to be not only an act of religion but also prayer in some measure. For those who are bound to the Divine Office do not pray in their own name, but in the name of the Church. Therefore, if they truly pronounce the words of the Office with the due intention and at least external attention, the Church seems to supply the internal attention otherwise necessary for true prayer. Therefore such a recitation of the Divine Office with external attention alone and with voluntary internal distraction has a twofold morality: the one good, because the one reciting wills to obey the precept of the Church; the other evil, because he wills to be voluntarily distracted during prayer.
178 Cf. St. Alphonsus, l.c., l. 3, n. 669.
357. 6. It seems to me that the essence of private prayer cannot subsist with external attention alone and with voluntary internal distraction.179 For prayer is an act of practical reason, as was said above from St. Thomas. Moreover, it seems to be an absurd contradiction that the same practical reason should at once elicit an act concerning God (prayer) and an entirely different act, for example concerning the devil (e.g., a voluntary thought about obscene things). Moreover, every prayer is an ascent of the mind to God, actual or at least virtual. Therefore, if through voluntary distraction the mind is knowingly called away from God, how can prayer then still persist? Can the human mind be at once elevated to God and at once knowingly not elevated?
179 The Angelic Doctor teaches (IV, dist. 15, q. 4, a. 2, quaestiunc. 4): "Attention in prayer must always remain virtually.... But it remains virtually when someone approaches prayer with the intention of impetrating something or of rendering due worship to God, even if in the continuation of the prayer the mind is carried away to other things; unless the wandering becomes so great that the force of the first intention entirely perishes, and therefore it is necessary that a man frequently recall his heart to himself." The Angelic Doctor has similar words in S. theol. 2, 2, q. 83, a. 13, ad 3: "If someone deliberately wanders in mind during prayer, this is a sin and impedes the fruit of prayer." Therefore, if the recalling of the heart is necessary, voluntary distraction also destroys virtual attention and consequently prayer itself. Concerning the mind of St. Antoninus see St. Alphonsus, l.c., l. 4, n. 177, and Concina, In Decal. l. 2, diss. 2, c. 9.
358. Objections. The reasons which are usually brought forward for the opposite opinion are not convincing. They say: 1. Prayer is a petition to God for fitting things. But it is not repugnant that our petitions can be represented before God even with an actual wandering of the mind. Just as, if someone were to recite before a king a speech composed for obtaining some favor, he would certainly pray by reciting it before the king, even if his mind were then distracted to other things; so also one reciting a prayer, notwithstanding internal and voluntary distraction, can still pray to God. This argument is repeated by all modern authors after Lugo, but in truth it seems to be very weak. For a king hearing the speech of such a voluntarily distracted man perceives nothing except the external words, which certainly bear the appearance of a petition, and consequently perhaps they are heard by the king; on the contrary, God, hearing the words of someone praying while voluntarily distracted, is not deceived by external words, but beholds his vain heart, and therefore not only will he not hear such a voluntarily distracted prayer, but rather will punish it. Therefore the comparison between a king and God limps and proves nothing. Nevertheless, something can be conceded to this argument. If one praying reads before the king not his own petition but that of another while voluntarily distracted, the king, knowing this voluntary distraction, is indeed offended by the irreverence of the one praying, but nevertheless perhaps will hear the petition on account of the other in whose name it was presented. Thus likewise a cleric reciting the Divine Office with voluntary distraction indeed sins and will be punished on account of the irreverence committed; but since he prays not in his own name but in the name of the Church, God can accept and even hear this prayer thus distracted. Hence such a cleric satisfies his obligation of reciting the Divine Office, provided, however, that he has the intention of satisfying, as was said above.
They say: 2. Internal attention cannot belong to the essence of vocal prayer, because otherwise a priest voluntarily distracted in the administration of Extreme Unction, whose essential form is deprecatory or a true prayer, would administer this sacrament invalidly; which authors nevertheless very commonly do not admit. The response to this argument is that the sacrament of Extreme Unction is not invalidated through the voluntary distractions of the priest administering it; but this proceeds from the fact that the priest prays not in his own name but in the name of the Church, and that the form of the sacraments externally pronounced seriously with the intention of doing what the Church does always produces its effect ex opere operato. Or, more briefly: the form of the sacrament of Extreme Unction pronounced by a voluntarily distracted priest is a true physical prayer and consequently produces the effect of the sacrament, but it is not a moral prayer (of the minister himself) or an act of the virtue of religion. He who desires more concerning this controversy should consult Concina, l.c.
359. The doctrine of St. Thomas concerning the necessity of attention.
Concerning the influence of attention upon the efficacy of prayer, the Angelic Doctor notes the following:180 "Concerning [vocal prayer] it must be known that something is called necessary in two ways: in one way, as that through which the end is better attained; and thus attention is absolutely necessary for prayer. In another way something is called necessary without which a thing cannot attain its effect. Now there is a threefold effect of prayer: the first is common to all acts informed by charity, which is to merit; and for this effect it is not required of necessity that attention be present to prayer throughout, but the force of the first intention with which someone approaches prayer renders the whole prayer meritorious, just as happens in other meritorious acts. The second effect of prayer is proper to it, which is to impetrate; and for this effect also the first intention, which God principally regards, suffices. But if the first intention is lacking, prayer is neither meritorious nor impetratory; for God does not hear that prayer to which he who prays does not attend. The third effect of prayer is that which it effects presently, namely a certain spiritual refreshment of the mind; and for this, attention in prayer is required of necessity." For it is established by experience that refreshment or affective devotion in prayer is not granted except to those who pray with actual attention.
180 S. theol. 2, 2, q. 83, a. 13.