Joshua 4:4-7

So Joshua called together the twelve men he had chosen—one from each of the tribes of Israel. He told them, “Go into the middle of the Jordan, in front of the Ark of the LORD your God. Each of you must pick up one stone and carry it out on your shoulder—twelve stones in all, one for each of the twelve tribes of Israel. We will use these stones to build a memorial. In the future your children will ask you, ‘What do these stones mean?’ Then you can tell them, ‘They remind us that the Jordan River stopped flowing when the Ark of the LORD’s Covenant went across.’ These stones will stand as a memorial among the people of Israel forever.”