John Wesley on Joshua 21:12

The fields and villages - That is, all beyond the two thousand cubits expressed, Numb 35:5. This is here mentioned, not as his peculiar case, but as one eminent instance, to shew, that it was so in all the rest of the cities here named; that the fields and villages thereof still belonged to the several tribes from whom the cities and their suburbs were taken; and to make the rest of the Israelites more chearfully resign part of their possessions to the Levites, because even Caleb did so, though his possession had been long before promised, and now actually given to him by God's special command, as a mark of honour and compensation for his long and faithful service.