Deuteronomy's Chapters 19 through 21 deal with what sort of killing is okay in the eyes of Yahweh.

Dealing with the Difference Between Murder and ManSlaughter

Chapter 19 is a sort of amendment to the Sixth Commandment: Thou shalt not murder.

First, anyone that kills his neighbor should be executed. Specifically, he ought to be killed by the victim's closest relative, whom the ancient Hebrews called 'the avenger of the blood'.

If he accidentally kills someone, then the accidental killer must flee to another city. But, if he returns to the city where the victim lived, then the 'avenger of the blood' may kill the guy.

However, before determining this there should also be three witnesses.

Killing in the Context of War

Deuteronomy, Chapter 20, if I can sum it up, says that first of all the Hebrews should not be afraid in battle because Yahweh has their back.

The chapter makes a distinction between two types of foes: distant enemies that are too far to be conquered, and nearby enemies that can be incorporated into the Israelite nation. Upon defeating distant opponents, Israelites should slay all the males but take for themselves all the cattle, children, and women for themselves.

But closeby cities, which Yahweh has essentially given to the Israelites, are to be utterly destroyed. Yahweh instructs the Israelites to kill all the lame, sickly, and elderly people; but to take young women and children.

In fact, as Chapter 21 explicitly says, if you find a beautiful woman among the captives, take her into your house, shave her head, let her mourn her dead parents, and then "go in unto her".

An ancient Israelite can even have two wives: "one loved, and one hated."

When Punishment Deserves Death

Chapter 21 even talks about what sort of infractions deserve death.

In particular, any child who is disobedient, and I mean thoroughly disobedient, then he should be taken to outskirts of the village and stoned to death by the villagers.

And if the punishment is hanging, the advice given by the author of Deuteronomy is that the person should be taken down before the end of the day. Apparently, the criminal who was hung is so vile that if he remained on the tree for more than one day, his vileness would contaminate the land.