Musnad Ahmad 33:431

Abu Ahmad narrated to us, Sufyan narrated to us, from Abdullah ibn Muhammad ibn Aqil, from Jabir, from the Prophet, peace and blessings of Allah be upon him: "That he forbade a man from wrapping himself in the *al-samma'* (a garment that leaves no opening for the arms), and from sitting in the *ihtiba'* (sitting with the knees drawn up to the chest) in a single garment, such that there is nothing of it over his private parts."