Three men for each tribe - i. e. 21 in all. Their duty would be to describe the land, especially with reference to the cities it contained Joshua 18:9, that Joshua might have the means of making a first apportionment among the tribes according to their varying numbers.
Related Commentaries of Joshua 18:4
Joshua 18:4
4 Give out from among you three men for each tribe: and I will send them, and they shall rise, and go through the land, and describe it according to the inheritance of them; and they shall come again to me.