Joshua 4:4-6

Young's Literal Translation

⁴ And Joshua calleth unto the twelve men whom he prepared out of the sons of Israel, one man -- one man out of a tribe;

⁵ and Joshua saith to them, `Pass over before the ark of Jehovah your God unto the midst of the Jordan and lift up for you each, one stone on his shoulder, according to the number of the tribes of the sons of Israel,

⁶ so that this is a sign in your midst, when your children ask hereafter, saying, What [are] these stones to you?