Numbers 35:13

35:13 These towns that you must give shall be your six towns for refuge.

Numbers 13:28

13:28 But the inhabitants are strong, and the cities are fortified and very large. Moreover we saw the descendants of Anak there.

Numbers 35:8

35:8 The towns you will give must be from the possession of the Israelites. From the larger tribes you must give more; and from the smaller tribes fewer. Each must contribute some of its own towns to the Levites in proportion to the inheritance allocated to each.