Joshua 3:3

the ark of the covenant called sometimes (i) "the Ark of God," 1 Samuel 3:3; sometimes (ii) "the Ark of the Testimony," Exodus 25:22. Here it means "the Ark of the Covenant of Jehovah," the Sacred Ark, an oblong chest of acacia wood, overlaid with the purest gold within and without, 2½ cubits in length, 1½ in breadth, 1½ in height. It contained the two stone tables, on both sides of which the Decalogue had been inscribed. Round the top ran a crown or wreath of pure gold, and upon it was the Mercy Seat, at either end of which were two golden Cherubim, with outspread wings and faces turned towards each other, and eyes bent downwards, as though desirous to look into its mysteries (1 Peter 1:12).

and go after it In the wilderness the Pillar of Cloud had led the way, now the Ark of the Covenant takes its place.