First Question: On the Essence of the New Law

St. Thomas, I-II, q. 106 and 107.

315. The new law properly and principally is the internal law implanted in us (q. 106, a. 1): for just as the natural law is the very light of our reason habitually showing what good is to be done and what evil is to be avoided, and the very habitual inclination to the good of reason, so the new law is the very habitual grace of the Holy Spirit, written in the heart of the faithful, in which the whole power of the law consists, since from the abundance of the light of faith and of the gifts (of understanding and knowledge) and of the illuminations of the Holy Spirit it indicates what is to be done in order to eternal life, and from the abundance of love and of grace sweetly inclining it also aids one in fulfilling it.

This is clear from the doctrine of the Apostle, who a) in Heb. VIII, 8-10, says that the prophecy of Jeremiah (XXXI, 33) concerning the new pact or testament has been fulfilled: "I will give My law in their inward parts and I will write it in their heart"; whence II Cor. III, 3: "you are the letter of Christ (ministered by us), and written not with ink but with the Spirit of the living God, not on tablets of stone but on fleshly tablets of the heart"; b) in Rom. III, 27, 31, he calls the very grace of faith a law, and opposes it as internal to the old law of exterior works; and c) in VIII, 2, he calls it the law of the Spirit of life, that is, of the Holy Spirit internally vivifying (for the spirit of life is something internal), which frees us from the law of sin and death, that is, from internal concupiscence, which the old law, as being external, could not conquer. Cf. Jn. VI, 44, 45 and Is. LIV, 13.

Secondarily, however, the new law is an external and written law, insofar as by words and writings it instructs the faithful concerning those things to be believed and done which dispose to grace or pertain to its use.

From this it follows that the new law justifies by its own power according as principally it is the very grace given interiorly, but not according to the precepts which secondarily pertain to it (a. 2).

316. The new law ought not to have been given from the beginning (a. 3).

1. because it is principally the grace of the Holy Spirit, which ought not to be given abundantly except after the redemption had been accomplished through Christ (Jn. VII, 39; Rom. VIII, 3); 2) because it is perfect: something ought not immediately be brought to perfection but successively, and therefore the imperfect law had to precede (Gal. IV, 24); 3) because it is the law of grace, and therefore it was necessary that man be left to his own powers in the Old Law, so that, by falling into sin and knowing his infirmity, he might recognize that he needed grace (Rom. V, 20).

317. The old and new law are one in species insofar as they tend to one thing, namely, that men be subject to God and have eternal life (q. 107, a. 1-4); nevertheless they are two in the degree of perfection, insofar as the Old is imperfect, but the New is perfect because it is the law of charity and of friendship with God.

Hence 1) the New fulfills the old (Mt. V, 17), because the perfect fulfills what is lacking to the imperfect: a) as to the end, which is the justification of men, which the old law could not effect but prefigured and promised would be effected by the new law; b) as to the precepts: for Christ not only confirmed the moral precepts of the law, but explained its true sense by showing that interior acts also are prohibited by it, indicated how it might be observed more safely, and superadded more perfect counsels (Mt. V-VII); 2) it is contained in the old as the tree in the seed; 3) it is less burdensome than the old (Mt. XI, 28), both in the number of precepts, because it adds few positive external precepts to natural law, and in the facility and delight of love with which it is fulfilled: for although it commands a more perfect mode of operating according to virtue and also prescribes justice in every interior affection, nevertheless these things are not burdensome to those who love God and have justice.

Whence the new law is altogether spiritual: a) it has a spiritual and eternal sanction (Mt. X, 28); therefore it calls blessed those who are poor, who mourn, who suffer persecution, because their reward is abundant in heaven (Mt. V, 3-12), and denounces temporal goods as impediments which delay us from the kingdom of heaven (Lk. VI, 24-25; Mt. XVI, 26);

b) it is a spiritual kingdom, for entering which faith in the Gospel, love of God and neighbor, imitation of Christ, and denial of self are required (Mt. V, 48);

c) the worship which it promotes, although it must be externally manifested, especially must be internal (Jn. IV, 23). Hence the ancient sacrifices, which chiefly consisted in external immolation, have been abolished, and there succeeds to them the sacrifice of Christ, who immolates not only His body, but His soul by most perfect obedience (Heb. X, 5-7). For this reason He wills His disciples also to offer spiritual victims (I Pet. II, 5; Mt. VI, 1).

1. Tanquerey, Theologia Moralis Fundamentalis, n. 247.

318. The new law was solemnly promulgated on the day of Pentecost, Jews from every nation being present; on that day it began to obligate in Jerusalem, but in other regions successively according to the time necessary for the knowledge of the law morally to be able of itself to arrive at them. But that this had been sufficiently done for the world then known is commonly believed to have occurred about 40 years after the death of the Savior (at the time of the fall of Jerusalem): for then the sound of the Apostles had gone out into every land (Rom. X, 18). Nevertheless for this reason the law had not been divulged, since knowledge of it had not yet in fact come to all.