Numbers 3:23 - Ellicott's Commentary On The Whole Bible

Behind the tabernacle westward. — As the position of the twelve tribes in respect of the tent of meeting had been already determined, so in this and the following verses the position of the priests and Levites is fixed. On the east side of the tent Moses and Aaron and Aaron’s sons were to encamp, on the south the Kohathites, on the west the Gershonites, on the north the Merarites.