Muwatta Malik Book 8, Hadith 31
Yahya related to me from Malik from Ibn Shihab from Said ibn al-
Musayyab from Abu Hurayra that some one asked the Messenger of Allah,
may Allah bless him and grant him peace about praying in one garment.
The Messenger of Allah, may Allah bless him and grant him peace, said,
"Do you all have two garments?"
Yahya related to me from Malik from Hisham ibn Urwa from his father that Umar ibn Abi Salama saw the Messenger of Allah, may Allah bless him and grant him peace, praying in one garment in the house of Umm Salama. He was completely covered by it, and had put both ends over his shoulders.
Yahya related to me from Malik from Ibn Shihab that Said ibn al- Musayyab said that Abu Hurayra was asked, "May a man pray in one garment?" He said, "Yes." The man then said to him "Do you do that?" and he replied, "Yes, I pray in one garment while my clothes are on the clothes-rack."