For three days and three nights preceding the exodus Moses hunted up and down through the land of Egypt for Joseph's coffin, because he knew that Israel could not leave Egypt without heeding the oath given to Joseph. But his trouble was in vain; the coffin was nowhere to be found. Serah, the daughter of Asher, met Moses, tired and exhausted, and in answer to her question about the cause of his weariness, he told her of his fruitless search.
Serah took him to the Nile river, and told him that the leaden coffin made for Joseph by the Egyptians had been sunk there after having been scaled up on all sides. The Egyptians had done this at the instigation and with the help of the magicians, who, knowing that Israel could not leave the country without the coffin, had used their arts to put it in a place whence it could not be removed.