Hadith of the Quran and Sunnah al-Thaqalayn" multiple times in multiple settings in multiple wordings. They argue that Muhammad said "Hadith al-Thaqalayn" at Mount Arafat during his Farewell Sermon, at Ghadir Khumm, in the mosque of Medinah, during his last illness, and at many other places and times. The Shi'as believe that Muhammad said this hadith so many times because he wanted to stress how important it was that the Muslims only take his own descendants as leaders. The Shi'as believe that this hadith is mutawattir, meaning that it has been related so many times by so many people that there is no doubt about its
Hadith of the Ark follows: Behold! The similitude of my Ahlul Bayt, is like that of the Ark of Noah: The one who embarks it, will have saved himself, and the one who turns away from it, is doomed. Many Sunni books narrate this Hadith. Some significant Sunni books that narrate this Hadith are: Al-Hakim al-Nisaburi, one of the greatest Sunni scholars, narrated this hadith as authentic (sahih) in his Mustadrak. Al-Heithami in his book ("written against Shia") states: By many narrations of this hadith which strengthen each other;""certainly Ahl al-Bayt are like the Ark of Noah, saved Whoever boarded"", and in Sahih Muslim