Sahih Al Bukhari Hadith Number 1165

Narrated `Aisha: The Prophet (peace be upon him) used to make the two rak`at before the Fajr prayer so light that I would wonder whether he recited Al-Fatiha (or not).

19  Prayer at Night (Tahajjud)
Hadith number 1165
Volume no 2
Chapter: 27 ( To offer two Rak’at before the Fajr prayer)