Musnad Abu Ya'la al-Mawsili 115:227

Ubayd Allah ibn Yazid ibn Zuray' narrated to us, from Sa'id ibn Abi 'Arubah, from Qatadah, that Anas ibn Malik narrated to them: That the Messenger of Allah (may Allah bless him and grant him peace) was among the lightest of people in prayer, while [still] completing it.