Joshua 4:1-6

And it came to pass, when all the nation were clean passed over the Jordan, that Jehovah spake unto Joshua, saying, Take you twelve men out of the people, out of every tribe a man, and command ye them, saying, Take you hence out of the midst of the Jordan, out of the place where the priests’ feet stood firm, twelve stones, and carry them over with you, and lay them down in the lodging-place, where ye shall lodge this night. Then Joshua called the twelve men, whom he had prepared of the children of Israel, out of every tribe a man: and Joshua said unto them, Pass over before the ark of Jehovah your God into the midst of the Jordan, and take you up every man of you a stone upon his shoulder, according unto the number of the tribes of the children of Israel; that this may be a sign among you, that, when your children ask in time to come, saying, What mean ye by these stones?