10 to the descendants of Aaron, who were members of the Kohathite clan within the tribe of Levi, since the sacred lot fell to them first: 11 Kiriath-arba (that is, Hebron), in the hill country of Judah, along with its surrounding pasturelands. (Arba was an ancestor of Anak.) 12 But the open fields beyond the town and the surrounding villages were given to Caleb son of Jephunneh as his possession.
Matthew Henry's Commentary on Joshua 21:10-12
Commentary on Joshua 21:9-42
(Read Joshua 21:9-42)
By mixing the Levites with the other tribes, they were made to see that the eyes of all Israel were upon them, and therefore it was their concern to walk so that their ministry might not be blamed. Every tribe had its share of Levites' cities. Thus did God graciously provide for keeping up religion among them, and that they might have the word in all parts of the land. Yet, blessed be God, we have the gospel more diffused amongst us.