6 that this may be a sign among you when your children ask in time to come, saying, 'What do these stones mean to you?' 7 Then you shall answer them that the waters of the Jordan were cut off before the ark of the covenant of the Lord; when it crossed over the Jordan, the waters of the Jordan were cut off. And these stones shall be for a memorial to the children of Israel forever." 8 And the children of Israel did so, just as Joshua commanded, and took up twelve stones from the midst of the Jordan, as the Lord had spoken to Joshua, according to the number of the tribes of the children of Israel, and carried them over with them to the place where they lodged, and laid them down there.
Matthew Henry's Commentary on Joshua 4:6-8
Commentary on Joshua 4:1-9
(Read Joshua 4:1-9)
The works of the Lord are so worthy of rememberance, and the heart of man is so prone to forget them, that various methods are needful to refresh our memories, for the glory of God, our advantage, and that of our children. God gave orders for preparing this memorial.