Sahih Bukhari
Fasting
Volume: 003 / Book Number: 031 / Hadith Number: 212
Narrated 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.