Musnad Ahmad 1156:15

'Abd al-Rahman narrated to us, from Malik, from Abu al-Aswad, from 'Urwah, from Zaynab bint Umm Salamah, from Umm Salamah, that she arrived while she was ill, and she mentioned that to the Prophet, peace and blessings of Allah be upon him. He said: "Perform Tawaf behind the people while you are riding." She said: So I heard the Prophet, peace and blessings of Allah be upon him, while he was at the Ka'bah, reciting [Surah] al-Tur.