Musnad Ahmad 1018:41

Muhammad ibn Ja'far narrated to us, Shu'bah narrated to us, he said: I heard Abu Malik al-Ashja'i narrating from Abu Salamah ibn 'Abd al-Rahman, he said: Someone who saw the Prophet, may Allah bless him and grant him peace, informed me that he was "praying in a single garment, having crossed its two ends over his shoulders."