Abu Dawud Book 2, Hadith Number 918.

Narated By AbuQatadah : We were sitting in the mosque when the Apostle of Allah (PBUH) came upon us carrying Umamah daughter of Abul’As ibn ar-Rabi’. Her mother was Zaynab daughter of the Apostle of Allah (PBUH). She (Umamah) was a child and he (the Prophet) was carrying her on his shoulder.

The Apostle of Allah (PBUH) led (the people) in prayer while she was on his shoulder. When he bowed he put her down and took her up when he got up. He kept on doing so until he finished his prayer.