Joshua 4:21-23

Then he spoke to the children of Israel, saying: “When your children ask their fathers in time to come, saying, ‘What are these stones?’ then you shall let your children know, saying, ‘Israel crossed over this Jordan on dry land’; for the LORD your God dried up the waters of the Jordan before you until you had crossed over, as the LORD your God did to the Red Sea, which He dried up before us until we had crossed over