In obedience to the command of God, the elders of the people were assembled, and before them Moses performed the wonders that were to be his credentials as the redeemer sent to deliver the people. Nevertheless, the deeds he did were not so potent in convincing them of the reality of the mission as the words wherein God had announced the approaching redemption to him, which he repeated in their ears.
The elders knew that Jacob had imparted to Joseph the secret mark designating the redeemer, and Joseph had in turn confided it to his brethren before his death. The last surviving one of the brethren, Asher, had revealed it to his daughter Serah, in the following words: "He that will come and proclaim the redemption with the words of God, 'I have surely visited you, and seen that which is done to you in Egypt,' he is the true redeemer."
Serah was still alive at Moses' return, and the elders betook themselves to her, and told her the words of Moses announcing the redemption. When she heard that his words had been the same as those Asher had quoted, she knew that he was the promised redeemer, and all the people believed in him.