Muwatta Malik Book 8, Hadith 35
Yahya related to me from Malik that he had heard from Jabir ibn
Abdullah that the Messenger of Allah, may Allah bless him and grant
him peace, said, "Let anyone who cannot find two garments pray in one
garment and wrap himself in it, and if the garment is short, let him
wrap it around his waist."
Malik said, "In my view it is
preferable for someone who prays in a single shirt to put a garment or
a turban over his shoulders."
Yahya related to me from Malik from Rabia ibn Abi Abd ar-Rahman that Muhammad ibn Amr ibn Hazm used to pray in a single long shirt.
Yahya related to me from Malik that he had heard that A'isha, the wife of the Prophet, may Allah bless him and grant him peace, used to pray in a shift and head-covering.