6 that this may be a sign among you. When your children ask in time to come, 'What do those stones mean to you?' 7 then you shall tell them that the waters of the Jordan were cut off before the ark of the covenant of the Lord. When it passed over the Jordan, the waters of the Jordan were cut off. So these stones shall be to the people of Israel a memorial forever." 8 And the people of Israel did just as Joshua commanded and took up twelve stones out of the midst of the Jordan, according to the number of the tribes of the people of Israel, just as the Lord told Joshua. And they carried them over with them to the place where they lodged and laid them down[1] 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.