Joshua 4:6-7

that this may be a sign among you. a When your children ask in time to come, ‘What do those stones mean to you?’ then you shall tell them that b the waters of the Jordan were cut off before the ark of the covenant of the  Lord. When it passed over the Jordan, the waters of the Jordan were cut off. So these stones shall be to the people of Israel c a memorial forever.”

Copyright information for ESV