Musnad Ahmad 31:909

'Affan narrated to us, Wahib narrated to us, 'Amr ibn Yahya narrated to us, from his father, from Abu Sa'id al-Khudri, who said: "The Messenger of Allah (peace and blessings of Allah be upon him) forbade fasting on two days: the day of al-Fitr and the day of al-Adha. And he forbade two types of clothing: the *samma'* (wrapping oneself in a garment such that no opening is left for the arms), and for a man to sit in a single garment while drawing his knees to his chest (ihtiba') without having another garment to cover his private parts. And he forbade prayer at two times: after the morning prayer until sunrise, and after the afternoon prayer until sunset."