Part V. On the Fifth Precept of the Decalogue

(St. Thomas, II-II, q. 64; St. Alphonsus, Theologia Moralis, book III, n. 363-411; Homo Apostolicus, tract 8, n. 1-32.)

By the fifth precept there is prohibited "the unjust killing, mutilation, beating, and other similar affliction" of oneself and of one's neighbor (St. Alphonsus, III, 363).

Killing is distinguished:

1. Into direct and indirect. It is direct when the act of killing, as such, is intended as an end or is assumed as a means by which another end is obtained. Otherwise it is indirect.

2. Into simple and qualified, according as circumstances which contain a special malice are not joined or are joined to it. Qualified killing is again distinguished:

a) Into parricide, by which name the killing of some relative is designated. In parricide there is added a sin against piety, if the killing concerns parents or other blood-relatives. Moreover, the killings of the aforesaid persons quite probably do not differ from one another in species.

b) Into regicide, which is the killing of a king, pope, or prince. In regicide, which is also called the crime of lese-majesty, there is added a sin against observance.

c) Into robbery-killing, which is killing done with the intention of plundering. Another species of injustice is added.

d) Into sacrilegious killing, which is the killing either of a sacred person or one done with profanation of a sacred thing or place. The sin of sacrilege is added.

Civil laws for the most part distinguish killing or voluntary homicide, and homicide that is voluntary and perpetrated with deliberate purpose.

With these things noted beforehand, we shall speak first about the killing of an innocent person, then about the killing of a criminal, finally about the killing of an unjust aggressor. About the killing of oneself, something was said in the treatise on charity (n. 523).