With the Three Before Him

When the Prophet ﷺ marched to Tabuk, he left 'Ali in charge of his family in Madinah. 'Ali was distressed to be left among the women and children, and the Prophet ﷺ said to him: "Are you not pleased to be to me as Harun was to Musa, except that there is no prophet after me?" (Sahih al-Bukhari 4416; Sahih Muslim 2404). On the way back from his Farewell Hajj, at Ghadir Khumm, the Prophet ﷺ said: "Whoever I am his mawla, 'Ali is his mawla" (Jami' al-Tirmidhi 3713).

Sunni scholars understand these words as a great declaration of 'Ali's rank and of the love and loyalty owed to him; Shi'a Muslims understand them as the Prophet's ﷺ designation of 'Ali as his successor. This is the root of the deepest difference between the two traditions, and it deserves to be discussed with knowledge and respect.

After the Prophet's ﷺ death, 'Ali gave his pledge to Abu Bakr — publicly, after Fatimah passed away (Sahih al-Bukhari 4241). When his own son Muhammad asked him who was the best of people after the Prophet ﷺ, he answered: Abu Bakr, then 'Umar (Sahih al-Bukhari 3671). Standing by 'Umar's bier, he said he wished to meet Allah with deeds like 'Umar's (Sahih al-Bukhari 3685). He pledged to 'Uthman, advised him, and during the siege sent his own sons to guard his door.