Joshua 4:21-23

He told the Israelites, “When some day your children ask you their parents, ‘What do these stones mean?’ you can explain to them, ‘This is where the Israelites crossed the Jordan on dry ground.’ For the Lord your God made the Jordan River dry up right in front of you so you all could cross, just as the Lord your God did at the Red Sea which he dried up so we could all cross.