The waters of Jordan were cut off before the ark of the covenant. — Observe that the act is indirectly ascribed to the ark of the covenant:
Related Commentaries of Joshua 4:7
Joshua 4:7
7 Then ye shall answer them, That the waters of Jordan were cut off before the ark of the covenant of the LORD; when it passed over Jordan, the waters of Jordan were cut off: and these stones shall be for a memorial unto the children of Israel for ever.