Joshua 18:4

Three men; three, not one, for more exact observation both of the measure and quality of the several portions, and for greater assurance and evidence of their care and faithfulness in giving in their account. Of each tribe; either one of each of these tribes, who were yet unprovided for; or rather, two of all the tribes, even of them who had already received their portions; which was highly expedient, that in case it should appear that there was not a sufficiency for each of these tribes who wanted their portions, their brethren might be more ready either to assist them in procuring more land, or to part with some of their own portion to them. Go through the land; which they might now safely do, because the terror of the late war was yet upon the Canaanites, who were loth to rouse so near and potent an enemy.