Waliuddin Abu Abdullah Mahmud Tabrizi, Selections from Muḥammadan Traditions…
“ He said, "O Abú Al Mandhar, dost thou know which verse from the Book of God which is with thee is greatest?" I said, "God, there is no God but He, the Living, the Self-subsisting. [1] "' Ubai said, 'And he struck me on my breast and said, "O Abú Al Mandhar, may knowledge be welcome to thee."'—Muslim. It is related from Ibn ʿAbbás that he said, 'Whilst Gabriel was sitting near the Prophet he heard a sound above him, and raised his head. And Gabriel said, "This is a door of heaven which has been opened to-day. It was never opened before to-day." And an angel came down from it. ”
