Sahih al-Bukhari
Sahih al-Bukhari 1104
Whoever offered Nawafil not after the compulsory Salat but before it
Arabic hadith text
وَقَالَ اللَّيْثُ حَدَّثَنِي يُونُسُ، عَنِ ابْنِ شِهَابٍ، قَالَ حَدَّثَنِي عَبْدُ اللَّهِ بْنُ عَامِرٍ، أَنَّ أَبَاهُ، أَخْبَرَهُ أَنَّهُ، رَأَى النَّبِيَّ صلى الله عليه وسلمصَلَّى السُّبْحَةَ بِاللَّيْلِ فِي السَّفَرِ عَلَى ظَهْرِ رَاحِلَتِهِ حَيْثُ تَوَجَّهَتْ بِهِ.
Translation
Narrated `Abdullah bin Amir that his father had told him that he had seen the Prophet (p.b.u.h) praying Nawafil at night on the back of his Mount on a journey, facing whatever direction it took.