Sahih Muslim Book: 7, Hadith: 1940

وَحَدَّثَنَاهُ عَبْدُ بْنُ حُمَيْدٍ، أَخْبَرَنَا عَبْدُ الرَّزَّاقِ، أَخْبَرَنَا مَعْمَرٌ، عَنِ الزُّهْرِيِّ، بِهَذَا الإِسْنَادِ. Ubayy b. Ka’b reported:I was in the mosque when a man entered and prayed and recited (the Qur’in) in a style to which I objected. Then another man entered (the mosque) and recited in a style different from that of his companion. When we had finished the prayer, we all went to Allah’s Messenger (may peace be upon him) and said to him: This man recited in a style to which I objected, and the other entered and recited in a style different from that of his companion. The Messenger of Allah (may peace be upon him) asked them to recite and so they recited, and the Apostle of Allah (may peace be upon him) expressed approval of their affairs (their modes of recitation). and there occurred In my mind a sort of denial which did not occur even during the Days of Ignorance. When the Messenger of Allah (may peace be upon him) saw how I was affected (by ...