7 Then you will say to them, Because the waters of Jordan were cut off before the ark of the Lord's agreement; when it went over Jordan the waters of Jordan were cut off: and these stones will be a sign for the children of Israel, keeping it in their memory for ever.
Matthew Henry's Commentary on Joshua 4:7
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.