Sahih Bukhari
Fighting for the Cause of Allah (Jihaad)
Volume: 004 / Book Number: 052 / Hadith Number: 243
Narrated Hisham's father:
Usama bin Zaid was asked at what pace the Prophet rode during Hajjat-ul-Wada' "He rode at a medium pace, but when he came upon an open way he would go at full pace."