Joshua 3:12

Now therefore take ye twelve men
For what end and purpose is not mentioned. Abarbinel is of opinion, that they were chosen and appointed, that every man might pitch upon and take a place for his tribe to encamp in, when they came on the other side Jordan: whether this was Joshua's view or no is not certain; however, the use he made of these, thus provided by divine direction, is related ( Joshua 4:2-4 ) ;

and these were to be taken out of the tribes of Israel, out of every
tribe a man;
Levi not reckoned, having no part in the land; and so we find that tribe left out in other accounts, when there was a choice of twelve men out of each of the tribes, ( Numbers 13:4 ) ( 34:19 ) .