Joshua 3:2-4

After three days the officers went throughout the camp, giving orders to the people: “When you see the ark of the covenant of the LORD your God, and the Levitical priests carrying it, you are to move out from your positions and follow it. Then you will know which way to go, since you have never been this way before. But keep a distance of about two thousand cubits between you and the ark; do not go near it.”