Albert Barnes Commentary Numbers 2:33-34

"But the Levites were not numbered among the children of Israel; as Jehovah commanded Moses. Thus did the children of Israel; according to all that Jehovah commanded Moses, so they encamped by their standards, and so they set forward, every one by their families, according to their fathers` houses." — Numbers 2:33-34 (ASV)

Such was the ideal form of the encampment in the wilderness: a form reproduced in the square court with which the temple was eventually surrounded, and in the vision of the heavenly city as seen by Ezekiel (Ezekiel 48:20), and by John (Revelation 21:16). Thus the camp of God’s earthly people was divinely ordered to set forth the completeness of His Church; and to illustrate by its whole arrangement, which was determined by the tabernacle in the center, both the dependence of all on God, and the access which all enjoyed to God.