Joshua 4:4-7, 19-24

Then Joshua called the twelve men whom he had appointed from the sons of Israel, one man from each tribe; and Joshua said to them, “Cross over again to the ark of the LORD your God into the midst of the Jordan, and each of you take up a stone on his shoulder, according to the number of the tribes of the sons of Israel, so that this may be a sign among you; when your children ask later, ‘What do these stones mean to you?’ then you shall say to them that 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 for Israel forever.”

Now the people came up from the Jordan on the tenth [day] of the first month and encamped at Gilgal on the eastern border of Jericho. And those twelve stones which they had taken from the Jordan, Joshua set up in Gilgal. He said to the sons of Israel, “When your children ask their fathers in time to come, ‘What do these stones mean?’ then you shall let your children know, ‘Israel crossed this Jordan on dry ground.’ For the LORD your God dried up the waters of the Jordan for you until you crossed over, just as the LORD your God did to the Red Sea, which He dried up before us until we had crossed; so that all the peoples of the earth may know [without any doubt] and acknowledge that the hand of the LORD is mighty and extraordinarily powerful, so that you will fear the LORD your God [and obey and worship Him with profound awe and reverence] forever.”