Numbers 35:17

You shall give three cities beyond the Jordan, and you shall give three cities in the land of Canaan. They shall be cities of refuge.

These six cities shall be refuge for the children of Israel, for the stranger, and for the foreigner living among them, that everyone who kills any person unwittingly may flee there.

“‘But if he struck him with an instrument of iron, so that he died, he is a murderer. The murderer shall surely be put to death.

Or if he struck him with a weapon of wood in the hand, by which a man may die, and he died, he is a murderer. The murderer shall surely be put to death.

The avenger of blood shall himself put the murderer to death. When he meets him, he shall put him to death.

If he shoved him out of hatred, or hurled something at him while lying in wait, so that he died,