Augustine of Hippo : "What about the prohibition, 'You shall not kill,' which is also there? If killing is evil in every respect, how will the just who, in obedience to a law, have killed many, be excused from this charge?" The answer to this question is that he does not kill who is the executor of a just command. — On Lying 13.23 Augustine of Hippo : It is significant that in Holy Scripture no passage can be found enjoining or permitting suicide either in order to hasten our entry into immortality or to void or avoid temporal evils. God's command, "You shall not kill," is to be taken as forbidding self-destruction, especially as it does not add "your neighbor," as it does when it forbids false witness, "You shall not bear false witness against your neighbor." — City of God 1.20 John Chrysostom : And that you may learn that we know this from the first, the Lawgiver, when He afterwards gave laws, and said, "Thou shalt not kill," did not add, "since murder is an evil thing," but simply said, "Thou shalt not kill;" for He merely prohibited the sin, without teaching. How was it then when He said, "Thou shalt not kill," that He did not add, "because murder is a wicked thing." The reason was, that conscience had taught this beforehand; and He speaks thus, as to those who know and understand the point. — HOMILIES CONCERNING THE STATUES 12.9 Philoxenus of Mabbug : And God also gave the law by the hand of Moses, which was filled with many and divers commandments, and to all the commandments He linked fear, for without fear the commandments would not be kept. "Thou shalt do no murder", and "whosoever slayeth shall be slain;" for the sickness He ordained the medicine of fear, that it might not increase and grow strong in iniquity. — 13 Ascetic Discourses, Discourse 6 -- First Discourse on the Fear of God