Numbers 35:34

“But if he did not lie in wait for him, but God let him fall into his hand, then I will appoint you a place to which he may flee.

“You shall send away both male and female; you shall send them outside the camp so that they will not defile their camp where I dwell in their midst.”

“Now this is the case of the manslayer who may flee there and live: when he strikes down his friend without premeditation, not hating him previously—

‘Atone for Your people Israel whom You have redeemed, O Yahweh, and do not place the guilt of innocent blood in the midst of Your people Israel.’ And the bloodguiltiness shall be atoned for them.

his corpse shall not hang all night on the tree, but you shall surely bury him on the same day (because cursed of God is he who is hanged), so that you do not make unclean your land which Yahweh your God gives you as an inheritance.

“Speak to the sons of Israel, saying, ‘Designate the cities of refuge, of which I spoke to you by the hand of Moses,

These were the appointed cities for all the sons of Israel and for the sojourner who sojourns among them, that whoever strikes down any person unintentionally may flee there and not die by the hand of the avenger of blood until he stands before the congregation.

“I will first doubly repay their iniquity and their sin because they have profaned My land; they have filled My inheritance with the carcasses of their detestable idols and with their abominations.”