Musnad Ahmad 27:1272

Hassan ibn Musa narrated to us, Ibn Lahi'ah narrated to us, Abu al-Zubayr narrated to us, 'Awn ibn 'Abd Allah informed us that he heard 'Abd Allah ibn 'Umar saying: We were sitting with the Messenger of Allah, peace and blessings of Allah be upon him, when a man said: "Allah is the Greatest, [much] greater; and praise be to Allah, much; and glory be to Allah, morning and evening." The Messenger of Allah, peace and blessings of Allah be upon him, said: "Who said these words?" The man said: "I did." The Messenger of Allah, peace and blessings of Allah be upon him, said: "By the One in Whose hand is my soul, I was looking at them ascending until the gates of the heaven were opened for them." Ibn 'Umar said: "By the One in Whose hand is my soul, I have not abandoned them since I heard them from the Messenger of Allah, peace and blessings of Allah be upon him." And 'Awn said: "I have not abandoned them since I heard them from Ibn 'Umar."