Sahih Bukhari Volume 008, Book 073, Hadith Number 234.
Hadith Section/Book: Sahih Bukhari Sahih Bukhari Book 73. Good Manners and Form (Al-Adab)
Narated By Ibn 'Abbas : Once I stayed overnight at the house of Maimuna and the Prophet was there with her. When it was the last third of the night, or some part of the night, the Prophet got up looking towards the sky and recited: 'Verily! In the creation of the heavens and the earth, and in the alternation of Night and Day, there are indeed signs for men of u understanding.' (3.190)