Joshua 3:2-4

2And it came to pass at the end of three days, that the officers went through the camp;

3and they commanded the people, saying, When ye see the ark of the covenant of Jehovah your 1God, and the priests the Levites bearing it, then remove from your place, and go after it;

4yet there shall be a distance between you and it, about two thousand cubits by measure. Ye shall not come near it, that ye may know the way by which ye must go; for ye have not passed this way heretofore.