Joshua 3:3-6

3and commanded the people, "As soon as you see the ark of the covenant of the Lord your God being carried by the Levitical priests, then you shall set out from your place and follow it.

4Yet there shall be a distance between you and it, about 2,000 cubits in length. Do not come near it, in order that you may know the way you shall go, for you have not passed this way before."

5Then Joshua said to the people, "Consecrate yourselves, for tomorrow the Lord will do wonders among you."

6And Joshua said to the priests, "Take up the ark of the covenant and pass on before the people." So they took up the ark of the covenant and went before the people.