Ubayy b. Ka‘b said:God’s messenger asked, “Abul Mundhir (this is Ubayy’s Kunya), do you know which verse of God’s Book that you have is greatest?” I replied, “God and His messenger know best.” He repeated his question and I said, “God, there is no god but He, the Living, the Eternal.” Thereupon he struck me on the breast and said, “May knowledge be pleasant for you, Abul Mundhir!” Muslim transmitted it.
Hadith Referenceمشكوة المصابيح / كتاب فضائل القرآن / 2122
Hadith Gradingالألبانی:صَحِيح | زبیر علی زئی:صحيح
Hadith Takhrij´تحقيق و تخريج: محدث العصر حافظ زبير على زئي رحمه الله` «رواه مسلم (810/258)»