630 - Al-Husayn ibn Hassan informed me that Abu 'Abd Allah was asked about the Sunnah regarding the Companions of Muhammad, and he said: "Abu Bakr, 'Umar, and 'Uthman [are mentioned] in the hadith of Ibn 'Umar, and 'Ali is among the Caliphs in the hadith of Safinah. 'Ali is among the Caliphs; the Caliphate is thirty years."
