Not one of all the Lord’s good promises to Israel failed

Joshua 21:1-45
The towns of the Levites in the territory held by the Israelites were forty-eight in all, together with their pasture lands. Each of these towns had pasture lands surrounding it; this was true for all these towns. 
So the Lord gave Israel all the land he had sworn to give their ancestors, and they took possession of it and settled there. Not one of all the Lord’s good promises to Israel failed; every one was fulfilled.
The Levites receive no tribal inheritance: God is their inheritance. But they are given 48 cities, with pasture, by the other tribes. This provision(規定) ensures that the leaders of the nation's faith and worship are dispersed(分散) throughout the land.
Why?
God is faithful instead of human being.
Assigned the territory by lot is equal and just to all tribes.
How?
Allot land to each tribes is a wisdom and needed, God's word never failed.