10 which went to the descendants of Aaron, one of the families of the Ko'hathites who belonged to the Levites; since the lot fell to them first. 11 They gave them Kir'iath-ar'ba (Arba being the father of Anak), that is Hebron, in the hill country of Judah, along with the pasture lands round about it. 12 But the fields of the city and its villages had been given to Caleb the son of Jephun'neh 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.