Treatise — Marc, Institutiones Morales
TREATISE V: On the Fifth Precept of the Decalogue
Thou shalt not kill.
(Exod., 20, 13).
St. Thomas, 2.2, q. 64 and 65; St. Alphonsus, III, 363; ed. G., I, p. 621; H. Ap., tr. VIII, n. 1-32; Lugo, disp. X, n. 1-55; Lessius, de Just., l. 2; Billuart, Diss. X, a. 3; Salmant., tr. 25 throughout; Laymann, sect. V, tr. III, P. III; Catech. Rom., de 5 Praec.; De Baets, Les bases de la Morale et du Droit; Nouv. Rev. Theol., vol. 37 (1905), p. 501; Van Gestel, de Just. et Lege civ.; Vermeersch, Quaest. de Just., n. 132-150.
- In the fourth precept we saw how man must have himself specially toward neighbor who is superior to him. In the six last precepts of the Decalogue we shall set forth the duties which must be observed toward EQUAL neighbors. There almost all things are ruled by strict or commutative justice. Among these duties the greatest is this, that neighbor not be harmed in his own person, as to the consistency of the person and the conservation of life. Therefore the precept concerning not killing comes here very fittingly.
This precept is formally negative, virtually affirmative.
- Insofar as it is negative, it PROHIBITS directly and primarily homicide, or the unjust killing of a man; but indirectly and consequently every unjust harming of neighbor in the goods of the body through mutilation, incarceration, beating, duel, war, etc. - It also prohibits all those things which proximately dispose to harm of this kind, such as hatred, anger, vengeance, and imprecations, which deservedly are called homicides of the heart and mouth (cf. n. 498).
It prohibits besides suicide, and unjust mutilation of oneself; and finally drunkenness, by which the use of reason, and therefore the proper life of man, is harmed.
- But insofar as this precept is virtually affirmative, it COMMANDS that we conserve our own and another's life in all licit ways, have peace with all, and patiently bear all inconveniences (cf. n. 476 seqq.).
Therefore there must be discussed: 1. justice and injury in general; - 2. homicide and its species; - 3. duel and war; - 4. suicide and drunkenness.3
(3) The actions concerning which there is discussion in the fifth precept are not all among those which have deformity always and everywhere inseparably attached, as, for example, adultery has. Several actions, weighed here, absolutely indeed import a certain deformity, but, with certain circumstances acceding, can become good (St. Thom., Quodl. IX, art. 15). Cf. what was said n. 295.