Deuteronomy 4:39-43

Therefore know today, and take it to your heart, that the Lord, He is God in heaven above and on the earth below; there is no other.

So you shall keep His statutes and His commandments which I am giving you today, so that it may go well for you and for your children after you, and that you may live long on the land which the Lord your God is giving you for all time.”

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

for one to flee there who unintentionally killed his neighbor, without having hatred for him in time past; and by fleeing to one of these cities he might live:

Bezer in the wilderness on the plateau for the Reubenites, Ramoth in Gilead for the Gadites, and Golan in Bashan for the Manassites.