Numbers 2:17-18

17“And the tabernacle of meeting shall move out with the camp of the Levites in the middle of the camps; as they camp, so they shall move out, everyone in his place, by their standards.

18“On the west side shall be the standard of the forces with Ephraim according to their armies, and the leader of the children of Ephraim shall be Elishama the son of Ammihud.”