Joshua 3:2-4

2After three days the officers went through the camp 3and commanded the people: “When you see the ark of the covenant of the LORD your God being carried by the Levitical priests, you are to set out from your positions and follow it. 4But keep a distance of about two thousand cubits1 between yourselves and the ark. Do not go near it, so that you can see the way to go, since you have never traveled this way before.”