The non-priestly Kohathites had been diminished by the destruction of Korah and his company Numbers 16. On comparing Numbers 26:57 following with Numbers 3:27 ff, two of the families of the Kohathites seem to have disappeared altogether. Hence, it is not surprising that the rest of the Kohathites were sufficiently accommodated in ten cities.

And the rest of the children of Kohath - That is, the remaining part of that family that were not priests, for those who were priests had their lot in the preceding tribes. Those, therefore, of the family of Kohath, who were simply Levites, and not of the priests or Aaron's family, (see Joshua 21:10), had their habitations in Ephraim, Dan, and the half tribe of Manasseh. It has been asked in what sense did the Levites possess those cities, seeing they had no inheritance? To which it may be answered that it is not likely the Levites had the exclusive property of the cities in which they dwelt, for it is evident that the other Israelites dwelt among them. We know, says Calmet, by history, that the cities of the Levites were almost entirely filled with Israelites of other tribes. For instance, Gibeah of Benjamin, which is here given to the Levites, Joshua 21:17, was always peopled by the Benjamites, as appears from the history of the Levite, whose wife was so horribly abused by them; Judges 19:22-27. Saul and all his family dwelt in the same city; and David and his court spent the first years of his reign at Hebron, which was also a city of the Levites, Joshua 21:10. It appears, therefore, that they had no other property in those cities than merely the right to certain houses, which they might sell, but always with the right of perpetual redemption, for they could finally alienate nothing; and if the possessor of such a house, having sold it, did not redeem it at the year of jubilee, it reverted to the Levites. And as to their lands for their cattle, which extended two thousand cubits without the city, these they were not permitted to sell: they were considered as the Lord's property. See Leviticus 25:32-34 (note), and the notes there. It is therefore very likely that, in the first instance, the Levites had simply the right to choose, in all the cities assigned them, the houses in which they were to dwell, and that those of the tribe to which the city belonged occupied all the other dwellings. There is also reason to believe that in process of time, when the families of the Levites increased, they had more dwellings assigned to them, which were probably built at the public expense. We may also observe that the Levites were not absolutely bound to live in these and no other cities: for when the tabernacle was at Nob, priests and Levites dwelt there, see 1 Samuel 21:1, etc.; and when the worship of God was established at Jerusalem, multitudes both of priests and Reviles dwelt there, though it was no Levitical city: as did the courses of priests afterwards at Jericho. This was a circumstance which Moses had foreseen, and for which he had provided. See Deuteronomy 18:6, etc.

And the rest of the children of Kohath,.... Which did not descend from him in the line of Amram and Aaron, but of Izhar, Hebron, and Uzziel, who were not priests, but Levites:

had by lot out of the families of the tribe of Ephraim, and out of the tribe of Dan, and out of the half tribe of Manasseh, ten cities; these other sort of Kohathites had their cities in tribes next to the other three where the Kohathites that were priests had theirs.

The rest of the Kohathites, i.e., the descendants of Moses, Izhar, Hebron, and Uzziel, received ten towns from Ephraim, Dan, and half Manasseh.

And the rest of the children of Kohath had by lot out of the families of the tribe of Ephraim, and out of the tribe of Dan, and out of the half tribe of Manasseh, ten cities.

21:5 Children of Kohath - Who were of Aaron's family. Ephraim, Dan, and Manesseh - Which tribes are nearest to the three former, and so the Kohathites are placed next to their brethren the Aaronites. Ten cities - Fewer than they gave out of the three former tribes, because their inheritance was less than the former.

21:1-8 The Levites waited till the other tribes were provided for, before they preferred their claim to Joshua. They build their claim upon a very good foundation; not their own merits or services, but the Divine precept. The maintenance of ministers is not a thing left merely to the will of the people, that they may let them starve if they please; they which preach the gospel should live by the gospel, and should live comfortably.