And they commanded the people, saying, When ye see the ark of the covenant of the LORD your God, and the priests the Levites bearing it, then ye shall remove from your place, and go after it.
And they commanded the people. The instructions given at this time and in this place were different from those described, Joshua 1:11, having a direct reference to the act and order of the approaching passage.
When ye see the ark ... The usual position of the ark, when at rest, was in the center of the camp; and during a march, in the middle of the procession. On this occasion it was to occupy the van, and be borne not by the Kohathite Levites, but the priests, as on all solemn and extraordinary occasions (cf. Numbers 4:15; Joshua 6:6; 1 Kings 8:3-6).
Then ye shall ... go after it,