On the west side, the divisions of Ephraim are to camp under their standard: The leader of the Ephraimites is Elishama son of Ammihud,
We have here the particular distribution of the twelve tribes into four squadrons, three tribes in a squadron, one of which was to lead the other two. Observe, 1. God himself appointed them their place, to prevent strife and envy among them.
Commenting on Numbers 2:3-34
On the west side shall be the standard of the camp of Ephraim, according to their armies,.... It was in the rear or behind, consisting of his tribe, and of the tribes of Manasseh and Benjamin, divided into several companies, and extended four miles, as the above Targum.
On the west side [shall be] the standard of the camp of Ephraim according to their armies: and the captain of the sons of Ephraim [shall be] Elishama the son of Ammihud. (f) Because Ephraim and Manasseh took the place of Joseph their father, they are taken as Rachel's children, so they and Benjamin make the third standard.