Musnad Ahmad 32:1271

'Abd al-Samad and 'Affan narrated to us, they said: Hammad narrated to us—the meaning [of the narration]—from Simak, from Anas ibn Malik, that the Messenger of Allah (peace and blessings of Allah be upon him) sent *Bara'ah* (Surah at-Tawbah) with Abu Bakr al-Siddiq. When he reached Dhu al-Hulayfah, 'Affan said: "No one shall deliver it except me, or a man from my household." So he sent it with 'Ali.