Deuteronomy 4:42 (KJV)

Thou shalt keep therefore his statutes, and his commandments, which I command thee this day, that it may go well with thee, and with thy children after thee, and that thou mayest prolong thy days upon the earth, which the Lord thy God giveth thee, for ever.

Then Moses severed three cities on this side Jordan toward the sunrising;

That the slayer might flee thither, which should kill his neighbour unawares, and hated him not in times past; and that fleeing unto one of these cities he might live:

Namely, Bezer in the wilderness, in the plain country, of the Reubenites; and Ramoth in Gilead, of the Gadites; and Golan in Bashan, of the Manassites.

And this is the law which Moses set before the children of Israel: