Sahih Bukhari | Volume 9 | Hadith Number 544

Narrated by Ibn 'Abbas
Once I stayed overnight at the house of (my aunt) Maimuna while the Prophet was with her, to see how was the night prayer of Allah s Apostle Allah's Apostle talked to his wife for a while and then slept. When it was the last third of the night (or part of it), the Prophet got up and looked towards the sky and recited the Verse: 'Verily! In the creation of the Heavens and the Earth... there are indeed signs for the men of understanding.' (3:190)

Then He got up and performed the ablution, brushed his teeth and offered eleven Rakat. Then Bilal pronounced the Adhan whereupon the Prophet offered a two-Rak'at (Sunna) prayer and went out to lead the people in Fajr (morning compulsory congregational prayer.