Joshua 4:1-3 (NKJV)
¹  And it came to pass, when all the people had completely crossed over the Jordan, that the LORD spoke to Joshua, saying:
²  “Take for yourselves twelve men from the people, one man from every tribe,
³  and command them, saying, ‘Take for yourselves twelve stones from here, out of the midst of the Jordan, from the place where the priests’ feet stood firm. You shall carry them over with you and leave them in the lodging place where you lodge tonight.’ ”