Numbers 35:11
"Then ye shall appoint you cities to be cities of refuge for you; that the slayer may flee thither, which killeth any person at unawares."
Cross References (ranked by relevance)
And if a man lie not in wait, but God deliver him into his hand; then I will appoint thee a place whither he shall flee.
And among the cities which ye shall give unto the Levites there shall be six cities for refuge, which ye shall appoint for the manslayer, that he may flee thither: and to them ye shall add forty and two cities.
Speak to the children of Israel, saying, Appoint out for you cities of refuge, whereof I spake unto you by the hand of Moses:
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: