Sahih Bukhari
Prayer at Night (Tahajjud)
Volume: 002 / Book Number: 021 / Hadith Number: 285
Narrated Ibn 'Umar:
The Prophet used to go to the Mosque of Quba (sometimes) walking and sometimes riding. Added Nafi (in another narration), "He then would offer two Rakat (in the Mosque of Quba)."