أما إنك ستلقى بعدي جهدا. قال: في سلامة من ديني؟ قال: في سلامة من دينك
(The Prophet salla Llahu ‘alayhi wa sallam said) “Verily, you shall encounter after me much difficulty.”
He (i.e. ‘Ali) said, “(Will it be) in a state wherein my din is sound?”
He salla Llahu ‘alayhi wa sallam said (in the affirmative), “In a state wherein your din will be sound.”
This hadith is reported by Ibn ‘Abbas, Abu ‘Ubaidah ibn al Hakam al Azdi, ‘Ali, and Anas radiya Llahu ‘anhum.
The Hadith of Ibn ‘Abbas
Al Hakim narrates — Ahmed ibn Sahl al Faqih (of Bukhara) informed us — Sahl ibn al Mutawakkil reported to us — Ahmed ibn Yunus reported to us — Muhammad ibn Fudayl reported to us — from Abu Hayyan al Taymi — from Sa’id ibn Jubayr — from Ibn ‘Abbas radiya Llahu ‘anhuma who said that Nabi salla Llahu ‘alayhi wa sallam was referring to ‘Ali radiya Llahu ‘anhu (in the above hadith).”
Al Hakim authenticated this hadith and al Dhahabi concurred, as per the conditions of Imams al Bukhari and Muslim.
According to al Albani, the authenticity of this hadith depends upon (the reliability of) Sahl ibn al Mutawakkil. He (i.e. al Albani) was not aware of who this person was. Al hamd li Allah, I (i.e. the author) determined who this narrator was. As I mentioned in the original work, all other shawahid (witness narrations) are inauthentic.
 Al Hakim al Naisaburi: Mustadrak al Hakim, hadith no. 4677.
 Ibn Hibban: Kitab al Thiqat, 8/294.
 Al Khalili: al Irshad fi Ma’rifat ‘Ulamaʾ al Hadith, 3/969.
 Al Albani: Silsilat al Ahadith al Da’ifah wa al Mawdu’ah, 10/556.