Sahih al-Bukhari 4569
Narrated Ibn `Abbas:
I stayed overnight in the house of my aunt Maimuna. Allah's Messenger (ﷺ) talked with his wife for a while 
and then went to bed. When it was the last third of the night, he got up and looked towards the sky and 
said: 
"Verily! In the creation of the Heavens and the Earth and in the alteration of night and day, there are 
indeed signs for men of understanding." (3.190) 
Then he stood up, performed ablution, brushed his teeth with a Siwak, and then prayed eleven rak`at. 
Then Bilal pronounced the Adhan (i.e. call for the Fajr prayer). The Prophet (ﷺ) then offered two rak`at 
(Sunna) prayer and went out (to the Mosque) and offered the (compulsory congregational) Fajr prayer.
حَدَّثَنَا سَعِيدُ بْنُ أَبِي مَرْيَمَ، أَخْبَرَنَا مُحَمَّدُ بْنُ جَعْفَرٍ، قَالَ أَخْبَرَنِي شَرِيكُ بْنُ عَبْدِ اللَّهِ بْنِ أَبِي نَمِرٍ، عَنْ كُرَيْبٍ، عَنِ ابْنِ عَبَّاسٍ ـ رضى الله عنهما ـ قَالَ بِتُّ عِنْدَ خَالَتِي مَيْمُونَةَ، فَتَحَدَّثَ رَسُولُ اللَّهِ صلى الله عليه وسلم مَعَ أَهْلِهِ سَاعَةً ثُمَّ رَقَدَ، فَلَمَّا كَانَ ثُلُثُ اللَّيْلِ الآخِرُ قَعَدَ فَنَظَرَ إِلَى السَّمَاءِ فَقَالَ ‏{‏إِنَّ فِي خَلْقِ السَّمَوَاتِ وَالأَرْضِ وَاخْتِلاَفِ اللَّيْلِ وَالنَّهَارِ لآيَاتٍ لأُولِي الأَلْبَابِ‏}‏، ثُمَّ قَامَ فَتَوَضَّأَ وَاسْتَنَّ، فَصَلَّى إِحْدَى عَشْرَةَ رَكْعَةً، ثُمَّ أَذَّنَ بِلاَلٌ فَصَلَّى رَكْعَتَيْنِ، ثُمَّ خَرَجَ فَصَلَّى الصُّبْحَ‏.‏