Numbers 2:2

Every man of the children of Israel shall pitch by his own standard, flag, or banner, with the ensign of their father's house. There were four of such large banners, one each for the four leading tribes, Judah, Reuben, Ephraim, and Dan, each of which had two other tribes on its side of the Tabernacle. Far off about the Tabernacle of the Congregation shall they pitch, that is, at some distance, and yet near enough to make their relation to the Sanctuary prominent.