Deuteronomy 19:6

“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.

then you shall select for yourselves cities to be your cities of refuge, that the manslayer who has struck down any person unintentionally may flee there.

‘And the cities shall be for you as a refuge from the avenger, so that the manslayer will not die until he stands before the congregation for judgment.

Then Moses set apart three cities across the Jordan to the east toward the sunrise,

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

Then she said, “Please let the king remember Yahweh your God, so that the avenger of blood will not continue to bring about ruin, so that they would not destroy my son.” And he said, “As Yahweh lives, not one hair of your son shall fall to the ground.”