The thirteen priestly cities (see the marginal references) were all in the tribes of Judah, Simeon, and Benjamin. Thus, as Calvin remarks, God so o…

Thus they gave to the children of Aaron the priest The families of the Kohathites, that part of them which descended from…

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 t…