Sahih Bukhari Volume 003, Book 031, Hadith Number 212.

Narated By Abu Sa'id : The Prophet forbade the fasting of 'Id-ul-Fitr and 'Id-ul-Adha (two feast days) and also the wearing of As-Samma' (a single garment covering the whole body), and sitting with one's leg drawn up while being wrapped in one garment. He also forbade the prayers after the Fajr (morning) and the 'Asr (afternoon) prayers.