Chapter 28 — Part III: The Decalogue — The Fifth Commandment
Section 5. Exceptions: The Killing Of Animals — With regard to the prohibitory part, it should first be taught what kinds of killing are not forbidden by this Commandment. It is not prohibited to kill animals; for if God permits man to eat them, it is also lawful to kill them. When, says St. Augustine, we hear the words, "Thou shalt not kill," we do not understand this of the fruits of the earth, which are insensible, nor of irrational animals, which form no part of human society.