The Messenger of Allah (ﷺ) taught me a soorah of ath-thalatheen, one of the family of Ha-Meem, i.e., al-Ahqaf. If a soorah contained more than thirty verses, it was called ath-thalatheen (thirty). So I went to the mosque in the morning and I saw a man reciting it in a way different from the way he had taught me. I said: Who taught you it? He said: The Messenger of Allah (ﷺ). I said to another man: Recite it. And he recited it in a way that was different from my recitation and that of my companion. I took them to the Prophet (ﷺ) and said: O Messenger of Allah, these two recite differently from me. He got angry and it could be seen from his face that he was upset, and he said: "Those who came before you were destroyed because of differences." Zirr said: There was a man with him and the man said: The Messenger of Allah (ﷺ) is instructing you each to recite as he was taught; those who came before you were only destroyed because of differences. 'Abdullah said: I do not know whether it was something that the Messenger of Allah (ﷺ) had told him privately or if he sensed what the Messenger of Allah (ﷺ) wanted to tell people. And that man was 'Ali bin Abi Talib.