when asked about the proof [of Allah] and the Imam after him, said, my son Muhammad will be the Imam and the proof after me. Whoever dies without acknowledging him [as the Imam] has died a death of ignorance. Know that certainly he will have an occultation, about which the ignorant will be left confused, the impugners will be ruined and those who predict a specific time [for his reappearance] will lie. Then he will emerge and it is as if I can see the white flags hovering above his head in Najaf [near] Kufa.'