Deuteronomy 20:19

"When thou shalt besiege a city a long time, in making war against it to take it, thou shalt not destroy the trees thereof by wielding an axe against them; for thou mayest eat of them, and thou shalt not cut them down; for is the tree of the field man, that it should be besieged of thee? Only of the trees of which thou knowest that they are not trees for food, thou shalt destroy and cut them down; and thou shalt build bulwarks against the city that maketh war with thee, until it fall."

This commandment to spare the fruit trees was squarely opposed to the "scorched earth" policy followed by many of the world's ruthless conquerors. It was the Jewish conceit that the primary reason for this commandment was that, "Since the Jews were certain to have victory (promised by God Himself), they would be injuring themselves by destroying the fruit trees which they would soon possess."[22] Scott properly identified this as another instance in which God sought, through instructions to Israel, to moderate certain cruelties of ancient warfare."[23] Also, it seems to us that Peter E. Cousins was correct in seeing here, "an ecological wisdom that the world is only now recognizing."[24] Blair listed other humane considerations evident in God's ancient instructions thus:

"Humane considerations appear in the allowance of exemptions in instances where men's hearts might be crushed without them, the unusual courtesies extended to certain captive women, such as a month's period of mourning, etc. (Deuteronomy 21:10-14), also the freedom of captives no longer wanted by the captor and the law against selling such a person into slavery."[25]

It is basic that Israel, at the time of the conquest of Canaan, was as bloody a nation as ever appeared upon the face of the earth, despite the fact of their actions coming under the direct commission of heaven, but it should be remembered that this was a bloody world at that period of its history, and that there was no other way for God to do what had to be done.