Joshua 3:1-5

1 Joshua rose up early in the morning; and they removed from Shittim, and came to the Jordan, he and all the children of Israel; and they lodged there before they passed over.  2 It happened after three days, that the officers went through the midst of the camp;  3 and they commanded the people, saying, When you see the ark of the covenant of Yahweh your God, and the priests the Levites bearing it, then you shall remove from your place, and go after it.  4 Yet there shall be a space between you and it, about two thousand cubits by measure: don't come near to it, that you may know the way by which you must go; for you have not passed this way heretofore.  5 Joshua said to the people, Sanctify yourselves; for tomorrow Yahweh will do wonders among you.