20:17. But shalt kill them with the edge of the sword, to wit, the Hethite, and the Amorrhite, and the Chanaanite, the Pherezite, and the Hevite, and the Jebusite, as the Lord thy God hath commanded thee:
20:18. Lest they teach you to do all the abominations which they have done to their gods: and you should sin against the Lord your God.
20:19. When thou hast besieged a city a long time, and hath compassed it with bulwarks, to take it, thou shalt not cut down the trees that may be eaten of, neither shalt thou spoil the country round about with axes: for it is a tree, and not a man, neither can it increase the number of them that fight against thee.
20:20. But if there be any trees that are not fruitful, but wild, and fit for other uses, cut them down, and make engines, until thou take the city, which fighteth against thee.
Deuteronomy Chapter 21
The expiation of a secret murder. The marrying a captive. The eldest son must not be deprived of his birthright for hatred of his mother. A stubborn son is to be stoned to death. When one is hanged on a gibbet, he must be taken down the same day and buried.
21:1. When there shall be found in the land, which the Lord thy God will give thee, the corpse of a man slain, and it is not known who is guilty of the murder,
21:2. Thy ancients and judges shall go out, and shall measure from the place where the body lieth the distance of every city round about:
21:3. And the ancients of that city which they shall perceive to be nearer than the rest, shall take a heifer of the herd, that hath not drawn in the yoke, nor ploughed the ground,
21:4. And they shall bring her into a rough and stony valley, that never was ploughed, nor sown: and there they shall strike off the head of the heifer: