On the contrary, It is written (1 Tim. 3:2, 3): "It behooveth . . . a bishop to be without crime [*Vulg.: 'blameless.' 'Without crime' is the reading in Tit. 1:7] . . . not given to wine, no striker."
I answer that, It is unlawful for clerics to kill, for two reasons. First, because they are chosen for the ministry of the altar, whereon is represented the Passion of Christ slain "Who, when He was struck did not strike [Vulg.: 'When He suffered, He threatened not']" (1 Pet. 2:23). Therefore it becomes not clerics to strike or kill: for ministers should imitate their master, according to Ecclus. 10:2, "As the judge of the people is himself, so also are his ministers." The other reason is because clerics are entrusted with the ministry of the New Law, wherein no punishment of death or of bodily maiming is appointed: wherefore they should abstain from such things in order that they may be fitting ministers of the New Testament.
Reply Obj. 1: God works in all things without exception whatever is right, yet in each one according to its mode. Wherefore everyone should imitate God in that which is specially becoming to him. Hence, though God slays evildoers even corporally, it does not follow that all should imitate Him in this. As regards Peter, he did not put Ananias and Saphira to death by his own authority or with his own hand, but published their death sentence pronounced by God. The Priests or Levites of the Old Testament were the ministers of the Old Law, which appointed corporal penalties, so that it was fitting for them to slay with their own hands.
Reply Obj. 2: The ministry of clerics is concerned with better things than corporal slayings, namely with things pertaining to spiritual welfare, and so it is not fitting for them to meddle with minor matters.
Reply Obj. 3: Ecclesiastical prelates accept the office of earthly princes, not that they may inflict capital punishment themselves, but that this may be carried into effect by others in virtue of their authority. _______________________
FIFTH ARTICLE [II-II, Q. 64, Art. 5]
Whether It Is Lawful to Kill Oneself?
Objection 1: It would seem lawful for a man to kill himself. For murder is a sin in so far as it is contrary to justice. But no man can do an injustice to himself, as is proved in Ethic. v, 11. Therefore no man sins by killing himself.
Obj. 2: Further, it is lawful, for one who exercises public authority, to kill evil-doers. Now he who exercises public authority is sometimes an evil-doer. Therefore he may lawfully kill himself.
Obj. 3: Further, it is lawful for a man to suffer spontaneously a lesser danger that he may avoid a greater: thus it is lawful for a man to cut off a decayed limb even from himself, that he may save his whole body. Now sometimes a man, by killing himself, avoids a greater evil, for example an unhappy life, or the shame of sin. Therefore a man may kill himself.