Adam Clarke Bible Commentary
Out of the tribe of Judah - Simeon, and - Benjamin, thirteen cities - These tribes furnished more habitations to the Levites in proportion than any of the other tribes, because they possessed a more extensive inheritance; and Moses had commanded, Num 35:8, From them that have many, ye shall give many; and from them that have few, ye shall give few: every one shall give of his cities unto the Levites, according to his inheritance. It is worthy of remark, that the principal part of this tribe, whose business was to minister at the sanctuary, which sanctuary was afterwards to be established in Jerusalem, had their appointment nearest to that city; so that they were always within reach of the sacred work which God had appointed them.
Carl Friedrich Keil and Franz Delitzsch Old Testament Commentary
Number of the cities which the different families of Levi received from each tribe. The tribe of Levi was divided into three branches, - The Gershonites, the Kohathites, and the Merarites (see Num 3 and Exo 6:16-19). The Kohathites again were divided into the four families of Amram, Izhar, Hebron, and Uzziel (Exo 6:18); and the family of Amram into two lines, consisting of the descendants of Moses and Aaron (Exo 6:20). The priesthood was committed to the line of Aaron (Num 18:1-7); but the other descendants of Amram, i.e., the descendants of Moses, were placed on a par with the other descendants of Levi, and numbered among the simple Levites (Num. 3; Ch1 6:1-7). The towns in which the different families of Levi were to dwell were determined by lot; but in all probability the towns which each tribe was to give up to them were selected first of all, so that the lot merely decided to which branch of the Levites each particular town was to belong.
Jos 21:4
The first lot came out for the families of Kohath, and among these again for the sons of Aaron, i.e., the priests. They received thirteen towns from the tribes of Judah, Simeon, and Benjamin. "This did not happen by chance; but God, according to His wonderful counsel, placed them just in that situation which He had determined to select for His own temple" (Calvin).
Jos 21:5
The rest of the Kohathites, i.e., the descendants of Moses, Izhar, Hebron, and Uzziel, received ten towns from Ephraim, Dan, and half Manasseh.
Jos 21:6
The Gershonites received thirteen towns from Issachar, Asher, Naphtali, and half Manasseh in Bashan.
Jos 21:7-8
The Merarites received twelve towns from Reuben, Gad, and Zebulun.
The number of towns thus assigned to the Levites will not appear too large, if we consider, (1) that judging from the number of towns in so small a land, the greater part of them cannot have been very large; (2) that the Levites were not the sole possessors of these towns, but simply received the number of dwelling-houses which they actually required, with meadow land for their cattle in the suburbs of the towns, whilst the rest of the space still belonged to the different tribes; and (3) that if the 23,000 males, the number of the Levites at the second census which was taken in the steppes of Moab, were distributed among the thirty-five towns, it would give 657 males, or 1300 male and female Levites for every town. On the other hand, offence has been taken at the statement, that thirteen towns were given up to the priests; and under the idea that Aaron could hardly have had descendants enough in Joshua's time from his two sons who remained alive to fill even two towns, to say nothing of thirteen, the list has been set down as a document which was drawn up at a much later date (Maurer, etc.). But any one who takes this ground not only attributes to the distribution commission the enormous shortsightedness of setting apart towns for the priests merely to meet their existing wants, and without any regard to the subsequent increase which would take place in their numbers, but also forms too large an estimate of the size of the towns, and too small an estimate of the number of the priests. Moreover, it was never intended that the towns should be filled with priests' families; and the number of priests alive at that time is not mentioned anywhere. But if we bear in mind that Aaron died in the fortieth year of the journeys of the Israelites, at the age of 123 years (Num 33:38), and therefore was eighty-three years old at the time of the exodus from Egypt, his descendants might have entered upon the fourth generation seven years after his death. Now his two sons had twenty-four male descendants, who were the founders of the twenty-four classes instituted by David (1 Chron 24). And if we only reckon six males to each of the next generations, there would be 144 in the third generation, who would be between the ages of twenty-five and thirty-five when the distribution of the land took place, and who might therefore have had 864 male children living at that time; so that the total number of males in the families of the priests might have amounted to more than 1000, that is to say, might have consisted of at least 200 families.
Jamieson-Fausset-Brown Bible Commentary
the lot came out for the families of the Kohathites--The Levites were divided into Kohathites, Gershonites, and Merarites. Among the former the family of Aaron were exclusively appointed to the priesthood, and all the rest were ranked in the common order of Levites. The first lot was drawn by the Kohathites; and the first of theirs again by the priests, to whom thirteen cities were granted, and ten to the rest of the Kohathites (Jos 21:5); thirteen to the Gershonites (Jos 21:6), and twelve to the Merarites (Jos 21:7).
John Gill Bible Commentary
And the lot came out for the family of the Kohathites,.... The first lot that was drawn out of the pot or urn was for the descendants of Kohath, a son of Levi:
and the children of Aaron the priest, which were of the Levites; who descended from Amram, the eldest son of Kohath, and these were not only Levites, but priests: these
had by lot out of the tribe of Judah, and out of the tribe of Simeon,
and out of the tribe of Benjamin, thirteen cities; which are after mentioned by name; and as these were priests, whose business was to serve in the temple, and at the altar, the cities assigned them by the lot, were, by the wise disposal of divine Providence, ordered them out of those tribes which lay nearest to Jerusalem; the place God had chosen to put his name in, where the temple would be built, and the altars erected for sacrifices and incense.