The order of march described here is different from 2:3–34. There, all three Levitical clans carried the tabernacle and its furnishings in the center of the camp. They marched between the groups led by Judah and Reuben, and the groups led by Ephraim and Dan.
In this passage, the arrangement is more detailed. The Gershonites and Merarites carried the structural parts of the tabernacle between Judah and Reuben. The Kohathites carried the most sacred furniture between Reuben and Ephraim.
This arrangement was practical. It gave the Gershonites and Merarites time to set up the tabernacle before the Kohathites arrived with the sacred objects. This plan also provided protection for the holy items.
In addition, this pattern spread the Levites among the tribes. Their presence among the people may have strengthened spiritual influence throughout the camp (compare Matthew 13:33; 16:6, 11–12; 1 Corinthians 5:6–7).