Musannaf Ibn Abi Shayba 3:2276

Abu Bakr narrated to us, he said: Marwan bin Mu'awiyah narrated to us, from Mansur bin Hayyan, he said: Sulayman bin Bashir al-Khuza'i informed me, from his maternal uncle Malik bin Abdullah, he said: I went on a military expedition with the Messenger of Allah (ﷺ). I never prayed behind an Imam who was lighter in prayer regarding the obligatory prayers than him.