Joshua 4:6; Joshua 4:7

6 "Let this be a sign among you, so that when your children ask later, saying, 'What do these stones mean to you?'

7 then you shall say to them, 'Because the waters of the Jordan were cut off before the ark of the covenant of the LORD ; when it crossed the Jordan, the waters of the Jordan were cut off.' So these stones shall become a memorial to the sons of Israel forever ."