The following Hadith, commonly quoted by Shia, is found in al-Mustadrak: 
        
          “Ahlul Bayt are like the Ark of Noah. Whoever embarked on it was saved. Whoever turned away perished.” 
        
        However, it is inauthentic.  Imam al-Dhahabi said in the Talkhis of   al-Mustadrak that this Hadith is a forgery.  The Isnad of the Hadith   contains Mufaddal ibn Salih, who Shaikh al-Islam Ibn Hajar in his Taqrib   called “weak” and whom Imam Bukhari referred to as “Munkhar al-Hadith”.    No version of this Hadith contains an acceptable chain of narrators.
        In any case, if we were to accept this Hadith as authentic, then it   would be used first and foremost in relation to the Prophet’s wives who   have most right to being called Ahlel Bayt.  The Shia are the ones who   have abandoned the Prophet’s wives.  If Ahlel Bayt are an Ark, then the   Shia have cut up that ship and punched a hole in part of it so that now   the entire boat is drowning.  On the other hand, the Ahlus Sunnah loves   and respect “the entire boat” (i.e. the entirity of the Ahlel Bayt).
        Article Written By:  Ibn al-Hashimi, www.ahlelbayt.com