Joshua 4:5-9
4:5 Joshua told them, “Go in front of the ark of the Lord your God to the middle of the Jordan. Each of you is to put a stone on his shoulder, according to the number of the Israelite tribes.
4:6 The stones will be a reminder to you. When your children ask someday, ‘Why are these stones important to you?’
4:7 tell them how the water of the Jordan stopped flowing before the ark of the covenant of the Lord. When it crossed the Jordan, the water of the Jordan stopped flowing. These stones will be a lasting memorial for the Israelites.”
4:8 The Israelites did just as Joshua commanded. They picked up twelve stones, according to the number of the Israelite tribes, from the middle of the Jordan as the Lord had instructed Joshua. They carried them over with them to the camp and put them there.
4:9 Joshua also set up twelve stones in the middle of the Jordan in the very place where the priests carrying the ark of the covenant stood. They remain there to this very day.