Musnad Ahmad 1007:68

Hajjaj ibn Muhammad narrated to us, Laith—meaning Ibn Sa’d—narrated to us, Sa’id ibn Abi Sa’id narrated to me, from ‘Amr ibn Sulaym al-Zuraqi that he heard Abu Qatadah say: "While we were sitting in the mosque, the Messenger of Allah (peace and blessings of Allah be upon him) came out to us carrying Umamah bint Abi al-‘As ibn al-Rabi’, whose mother was Zaynab, the daughter of the Messenger of Allah (peace and blessings of Allah be upon him), and she was a young girl. He carried her on his shoulder. The Messenger of Allah (peace and blessings of Allah be upon him) prayed while she was on his shoulder; he would put her down when he bowed, and he would return her to his shoulder when he stood up. The Messenger of Allah (peace and blessings of Allah be upon him) prayed while she was on his shoulder, then he stood until he finished his prayer, doing that with her."