Musnad Ahmad Hadith 21186

Affan narrated to us, Hammad ibn Salamah narrated to us, Asim ibn Bahdalah informed us, from Zir ibn Hubaysh, who said: I said to Ubayy ibn Ka'b, "Indeed, Ibn Mas'ud did not write the two chapters of seeking refuge (al-Mu'awwidhatayn) in his mushaf." He said: "I bear witness that the Messenger of Allah, peace and blessings be upon him, informed me that Jibril said to him: 'Say: I seek refuge with the Lord of the daybreak' __QUR_113_1__, so I said it. Then he said: 'Say: I seek refuge with the Lord of mankind' __QUR_114_1__, so I said it. So we say what the Prophet, peace and blessings be upon him, said."