Musnad Ahmad 30:3018

Yahya narrated to us, from Muhammad, who said: Abu Salamah narrated to me, from Abu Hurayrah, from the Prophet (peace and blessings of Allah be upon him): "He forbade two transactions in one transaction, and two modes of dress: that one of you should wrap himself in the *samma'* (a way of wrapping the garment that leaves no opening for the arms) in a single garment, or that one should sit in the *ihtiba'* (sitting with the knees drawn up to the chest) in a single garment, with nothing between him and the sky."