Joshua 21:43

We have here the conclusion of this whole matter, the foregoing history summed up, and, to make it appear the more bright, compared with the promise of which it was the full accomplishment. God's word and his works mutually illustrate each other. The performance makes the promise appear very true and the promise makes the performance appear very kind. I. God had promised to give the seed of Abraham the land of Canaan for a possession, and now at last he performed this promise (Jos 21:43): They possessed it, and dwelt therein. Though they had often forfeited the benefit of that promise, and God had long delayed the performance of it, yet at last all difficulties were conquered, and Canaan was their own. And the promise of the heavenly Canaan is as sure to all God's spiritual Israel, for it is the promise of him that cannot lie. II. God had promised to give them rest in that land, and now they had rest round about, rest from the fatigues of their travel through the wilderness (which tedious march, perhaps, was long in their bones), rest from their wars in Canaan, and the insults which their enemies there had at first offered them. They now dwelt, not only in habitations of their own, but those quiet and peaceable ones; though there were Canaanites that remained, yet none that had either strength or spirit to attack them, nor so much as give them an alarm.

— Matthew Henry's Concise Commentary (public domain)

GOD GAVE THEM REST. (Jos 21:43-45) the Lord gave unto Israel all the land which he sware to give unto their fathers--This is a general winding up of the history from the thirteenth chapter, which narrates the occupation of the land by the Israelites. All the promises made, whether to the people or to Joshua (Jos 1:5), had been, or were in the course of being fulfilled; and the recorded experience of the Israelites (Jos 21:45), is a ground of hope and confidence to the people of God in every age, that all other promises made to the Church will, in due time, be accomplished. Next: Joshua Chapter 22

— Jamieson-Fausset-Brown Commentary (public domain)