Joshua 4:4-7

So Joshua summoned the twelve men he had selected from the Israelites, one per tribe. Joshua instructed them, “Walk out to the middle of the riverbed to the ark of YAHWEH your God. Each of you choose a stone and lift it up onto your shoulder—one stone for each tribe. The stones will always be a sign to you. Someday, when your children ask you, ‘Why are these stones so important?’ tell them, ‘The Jordan stopped flowing in front of the ark of the covenant of YAHWEH—the floodwaters were completely cut off.’ These stones will serve as a memorial for Israel forever.”