These six cities will serve as a refuge for the Israelites and for the foreigner or stranger among them, so that anyone who kills a person unintentionally may flee there.

Leviticus 4:2
"Tell the Israelites to do as follows with one who sins unintentionally against any of the LORD's commandments and does what is forbidden by them:

Numbers 35:11
designate cities to serve as your cities of refuge, so that a person who kills someone unintentionally may flee there.

2 Samuel 14:14
For surely we will die and be like water poured out on the ground, which cannot be recovered. Yet God does not take away a life; but He devises ways that the banished one may not be cast out from Him.

These six cities shall be a refuge, both for the children of Israel, and for the stranger, and for the sojourner among them: that every one that kills any person unawares may flee thither.