Your wives, your little ones, and your livestock, shall live in the land which Moses gave you beyond the Jordan; but you shall pass over before your brothers armed, all the mighty men of valor, and shall help them
The wives and children stayed behind as agreed in Numbers 32, while every able-bodied man crossed armed and in military order, though "before your brethren" means in their company, not at the vanguard, since Judah's standard went first. Of the hundred thirty thousand capable of bearing arms, only forty thousand actually went with Joshua.
AI summary
Joshua recalled the condition Moses had set when he granted them the eastern land: they must fulfill their oath to fight. The word "all" should not be pressed, only about 40,000 of the 110,000 fighting men crossed Jordan; the rest remained to defend their families, flocks, and territory they had taken.
AI summary
Commenting on Joshua 1:12-18
ye shall pass . . . armed--that is, officered or marshalled under five leaders in the old and approved caravan order (see on Exo 13:18). all the mighty men of valour--The words are not to be interpreted strictly as meaning the whole, but only the flower or choice of the fighting men (see on Jos 4:12). Next: Joshua Chapter 2