Objection 1: It would seem lawful for clerics to kill evil-doers. For clerics especially should fulfil the precept of the Apostle (1 Cor. 4:16): "Be ye followers of me as I also am of Christ," whereby we are called upon to imitate God and His saints. Now the very God whom we worship puts evildoers to death, according to Ps. 135:10, "Who smote Egypt with their firstborn." Again Moses made the Levites slay twenty-three thousand men on account of the worship of the calf (Ex. 32), the priest Phinees slew the Israelite who went in to the woman of Madian (Num. 25), Samuel killed Agag king of Amalec (1 Kings 15), Elias slew the priests of Baal (3 Kings 18), Mathathias killed the man who went up to the altar to sacrifice (1 Mac. 2); and, in the New Testament, Peter killed Ananias and Saphira (Acts 5). Therefore it seems that even clerics may kill evil-doers.
Obj. 2: Further, spiritual power is greater than the secular and is more united to God. Now the secular power as "God's minister" lawfully puts evil-doers to death, according to Rom. 13:4. Much more therefore may clerics, who are God's ministers and have spiritual power, put evil-doers to death.
Obj. 3: Further, whosoever lawfully accepts an office, may lawfully exercise the functions of that office. Now it belongs to the princely office to slay evildoers, as stated above (A. 3). Therefore those clerics who are earthly princes may lawfully slay malefactors.
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.