Joshua 4:1-7

"And it came to pass when all the nation had 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 in the midst of the Jordan, and take you up every man of you a stone upon his shoulder, according to 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, What mean ye by these stones? then ye shall say unto them, Because the waters of the Jordan were cut off before the ark of the covenant of Jehovah; when it passed over the Jordan, the waters of the Jordan were cut off; and these stones shall be for a memorial unto the children of Israel forever."

The use of cairns of stones as memorials is a mark of the extreme antiquity of this narrative. (See the introduction to Joshua.)

"Forever ..." Now, that cairn is invisible; but the institutions the two cairns (one in the midst of the river, and the other at Gilgal) typified, namely, Christian baptism and the Lord's Supper, shall indeed last forever! The instructions here show clearly that the "crossing" is still under way, and that the priests were still standing in the midst of the Jordan. Blair and others have supposed that the Crossing was indeed complete, and that these twelve special representatives of Israel went back to the place where the priests had stood to gather the stones. It is very difficult to reconstruct all of the action precisely. In any case, the purpose of the twelve and the memorial was to show the participation of all of the twelve tribes of Israel in this event.