Musannaf Ibn Abi Shayba 3:783

Abu Bakr narrated to us, he said: Ibn 'Uyaynah narrated to us, from al-Zuhri, from Sa'id ibn al-Musayyib, from Abu Hurayrah, who said: A man came to the Prophet, may Allah bless him and grant him peace, and said: "Does one of us pray in a single garment?" He said: "Does every one of you have two garments?" Abu Hurayrah said to the one who asked him: "Do you know Abu Hurayrah? For he prays in one garment."