Musnad Ahmad 482:34

Ishaq ibn Ibrahim al-Razi narrated to us, Salama ibn al-Fadl narrated to us, he said: Muhammad ibn Ishaq narrated to me, from Yazid ibn Abi Habib, from Marthad ibn Abdullah al-Yazani, from Uqbah ibn Amir al-Juhani, he said: The Messenger of Allah, may Allah bless him and grant him peace, said to me: "Recite the two verses from the end of Surat al-Baqarah, for I was given them from beneath the Throne."