Joshua 4:10-12

Young's Literal Translation

¹⁰ And the priests bearing the ark are standing in the midst of the Jordan till the completion of the whole thing which Jehovah commanded Joshua to speak unto the people, according to all that Moses commanded Joshua, and the people haste and pass over.

¹¹ And it cometh to pass when all the people have completed to pass over, that the ark of Jehovah passeth over, and the priests, in the presence of the people;

¹² and the sons of Reuben, and the sons of Gad, and the half of the tribe of Manasseh, pass over, by fifties, before the sons of Israel, as Moses had spoken unto them;