Joshua 21:4

Which three tribes were nearest to the temple, where their business lay. Thirteen cities; for though the priests were now few enough for one city, yet respect was to be had to their succeeding numbers; this division being made for all future generations. And seeing the Levites might sell their houses until the jubilee, Leviticus 25:33, much more might they let them; and therefore it is probable their cities were not very long uninhabited, many being inclined to dwell with them by virtue of relations contracted with them, or dependence upon or expectation from them; or out of respect to the service of God, and the good of their souls.