It is narrated from Sayyiduna Abdullah bin Mas'ud (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "The millstone of Islam will turn for thirty-five or thirty-six years. Then if they perish, it will be the way of those who perished; and if their religion endures for them, it will then endure for seventy years." Sayyiduna Umar (may Allah be pleased with him) said: O Messenger of Allah! Is this of the period that remains or of the period that has passed? He (peace and blessings be upon him) said: "Of the period that remains." This hadith has an authentic chain (sahih al-isnad), but the two Shaykhs did not record it. [Mention of the pledge of allegiance to the Commander of the Believers, Sayyiduna Ali bin Abi Talib (may Allah be pleased with him)] Imam al-Hakim (may Allah have mercy on him) said: The narrations differ about the time of his pledge of allegiance. It is said that the pledge took place four days after the martyrdom of Sayyiduna Uthman (may Allah be pleased with him); some said five days and some said three days. One view is that the pledge took place on Friday, 25 Dhu al-Hijjah, and another view is that the pledge took place immediately after the martyrdom of Sayyiduna Uthman (may Allah be pleased with him) in the house of Amr bin Mihsan al-Ansari. But the most authentic narration is that he refused to accept the pledge until Sayyiduna Uthman (may Allah be pleased with him) had been buried; then he accepted the pledge openly on the pulpit of the Messenger of Allah (peace and blessings be upon him), and the first to pledge allegiance was Sayyiduna Talhah (may Allah be pleased with him), and he said: This is a pledge that will be broken.