It is narrated from Sayyiduna Anas bin Malik (may Allah be pleased with him) that the Prophet (peace and blessings be upon him) said to Sayyiduna Ali (may Allah be pleased with him): "After me, you will make clear to my Ummah the matters in which they differ." This hadith is sahih (authentic) on the condition of the two Shaykhs (Bukhari and Muslim), but they did not record it.

It is narrated from Sayyiduna Abu Sa'id al-Khudri (may Allah be pleased with him) that he said: We were on a journey with the Messenger of Allah (peace and blessings be upon him) when the strap of his (peace and blessings be upon him) sandal broke, and Sayyiduna Ali (may Allah be pleased with him) stayed behind to mend it. He (peace and blessings be upon him) walked a short distance, then stopped and said: "Among you is a man who will fight over the interpretation (ta'wil) of the Qur'an (preserving its correct meaning) just as I fought over its revelation (tanzil, the conveying of the revelation)." At this, the Companions raised their heads eagerly to look, and among them were Sayyiduna Abu Bakr and Sayyiduna Umar (may Allah be pleased with them both). Sayyiduna Abu Bakr asked: Is it I? He (peace and blessings be upon him) said: "No." Then Sayyiduna Umar (may Allah be pleased with him) asked: Is it I? He (peace and blessings be upon him) said: "No; rather, it is the one who is mending the sandal (that is, Ali)." The narrator says: Then we came to Sayyiduna Ali (may Allah be pleased with him) and gave him this glad tidings, but he (remained absorbed in his work and) did not even raise his head, as though he had already heard it from the Messenger of Allah (peace and blessings be upon him). This hadith is sahih (authentic) on the condition of the two Shaykhs (Bukhari and Muslim), but they did not record it.