Musnad Ahmad 25:63

Sufyan narrated to us, Sulayman ibn Suhaym narrated to us—Sufyan said: I did not memorize from him anything other than it—he said: I heard it from Ibrahim ibn Abdullah ibn Ma'bad ibn Abbas, from his father, from Ibn Abbas, who said: The Messenger of Allah, peace and blessings of Allah be upon him, drew back the curtain while the people were in rows behind Abu Bakr, and he said: "O people, there remains nothing of the glad tidings of prophethood except the righteous vision, which a Muslim sees or is seen for him." Then he said: "Verily, I have been forbidden to recite [the Quran] while bowing or prostrating. As for bowing, then glorify the Lord therein; and as for prostrating, then strive in supplication, for it is worthy that it be answered for you."