Joshua 3:3

And they commanded the people
In the name of Joshua, by whom they were sent:

saying, when ye see the ark of the covenant of the Lord your God, and
the priests the Levites bearing it:
the Targum reads, the priests and Levites; so the Septuagint: it was the business of the Levites, particularly the Kohathites, to bear the ark in journeying, but here the priests, who also were Levites, were to carry it: it is remarked in the Talmud ^F16, that there are three places in which the priests are said to bear the ark; here, and when they surrounded Jericho, ( Joshua 6:6 ) ; and when it was returned to its place in the times of David, ( 2 Samuel 15:29 ) ; and Kimchi and Abarbinel observe a fourth, when it was brought into Solomon's temple, ( 1 Kings 8:6 ) ;

then ye shall remove from your place, and go after it;
their usual signal for marching was the cloud, when that was taken up, ( Numbers 9:17 ) , &c. but now the ark, the clouds of glory having removed at the death of Moses, and were seen no more, as Abarbinel and other Jewish writers observe; and therefore it was proper the Israelites should be made acquainted with this signal; for, as Jarchi says, this journey was different from all the journeys (though that of the three days journey from Sinai must be excepted, ( Numbers 10:33 ) ), for all the time Moses was in being, the pillar of cloud marched first and showed them the way, and the ark moved after two of the standards (Judah and Reuben), and now the ark went first: the cloud was a figure of the dark and cloudy dispensation of the law, particularly the ceremonial law, the shadow of good things to come, and which continued only during the former state, and discontinued to be of any use when the Mosaic dispensation ceased, and when Joshua or Jesus was come: the ark was a type of Christ, the forerunner for us entered, and whom we are to follow whithersoever he goes or directs to, in the exercise of grace and performance of duty; and the ark being carried now by different persons, may denote that Christ was held forth in a weaker manner under the legal dispensation, and by his apostles and ministers under the Gospel dispensation in a clearer and stronger manner, and who are to be followed no further or longer than as they bear the ark or direct to Christ.