Numbers 2:2-3

2The children of Israel shall encamp every one by his standard, with the ensign of their father's house; round about the tent of meeting, afar off, opposite to it shall they encamp.

3And [for] those encamping eastward toward the sun-rising [there shall be] the standard of the camp of Judah according to their hosts; and the prince of the sons of Judah shall be Nahshon the son of Amminadab;