Joshua 4:7

4 So Joshua sent for the twelve men, whom he had ready, one man out of every tribe of the children of Israel,

5 And he said to them, Go over before the ark of the Lord your God into the middle of Jordan, and let every one of you take up a stone on his back, one for every tribe of the children of Israel:

6 So that this may be a sign among you; when your children say to you in time to come, What is the reason for these stones?

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.

8 So the children of Israel did as Joshua gave them orders, and took twelve stones from the middle of Jordan, as the Lord had said to Joshua, one for every tribe of the children of Israel; these they took across with them to their night's resting-place and put them down there.

9 And Joshua put up twelve stones in the middle of Jordan, where the feet of the priests who took up the ark of the agreement had been placed: and there they are to this day.

10 For the priests who took up the ark kept there in the middle of Jordan till all the orders given to Joshua by Moses from the Lord had been done: then the people went over quickly.