John Wesley on Joshua 21:3

The children of Israel gave - Probably they gave the Levites promiscuously such cities as God commanded, and the lot appropriated them to their several houses or families. Out of their inheritance - That is, out of their several possessions; that the burden might be equally divided; and, that the Levites being dispersed among the several tribes, according to Jacob's prediction, Gen 49:7, might more easily, and effectually teach the Israelites God's law and judgments, which they were engaged to do, Deu 33:10, and that the people might upon all occasions resort to them, and enquire the meaning of the law at their mouths. And suburbs - Not only the use, but the absolute dominion of them, as is manifest both from ver.Jos 21:11,12, where a distinction is made between the city and suburbs of Hebron, and the fields and villages thereof; (the former given to the Levites, the latter to Caleb;) and from the return of these cities in the Jubilee, unto the Levites as to their proper owners, Lev 25:33,34.