Abdullah bin Buraydah narrates from his father (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) forbade praying wrapped in a single sheet without its right end over the left shoulder and its left end over the right shoulder; likewise he (peace and blessings be upon him) also forbade praying in trousers alone without an upper sheet.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 3276