There were 12 towns in which the Merarites resided: four in Zebulun (vv. 34-35), four in Reuben (vv. 36-37), and four in Gad (vv. 38-39).
In all, the Levites received 48 cities with their surrounding pasture lands including the six cities of refuge (vv. 41-42). God provided so that the Levites, whose responsibilities included the teaching and counseling of the other Israelites in the law, were not far from anyone in Israel. They were to provide a positive spiritual influence on the whole nation.187
"For Christians, the allotment of Levitical towns from each tribe illustrates the principle of returning to God a portion of what has been given to them. These gifts are then used to support others in need and to encourage the proclamation of the faith (cf. Acts 2:44-47; Rom. 15:26-27; Phil. 4:10-18)."188
"Take special care of the poor clergy! This is the theme of the complex formed by Num 35 and Josh 21, along with the relevant Deuteronomic laws."189
