Musannaf Ibn Abi Shayba 3:2285

4662. Al-Thaqafi narrated to us, from Abdullah bin Uthman bin Jubayr, from Nafi’ bin Sarjas Abu Sa’id, that he heard Abu Waqid al-Laythi, a companion of the Prophet (may Allah bless him and grant him peace), and prayer was mentioned in his presence. He said: "The Messenger of Allah (may Allah bless him and grant him peace) was the lightest of people upon the people, and the most constant of them upon himself."