Numbers 2:2-3

The children of Israel shall encamp every man by his own standard, with the ensigns of their fathers’ houses: over against the tent of meeting shall they encamp round about. And those that encamp on the east side toward the sunrising shall be they of the standard of the camp of Judah, according to their hosts: and the prince of the children of Judah shall be Nahshon the son of Amminadab.