Sahih al-Bukhari 1103
Sahih al-Bukhari · Book 18: Shortening the Prayers (At-Taqseer) · Whoever offered Nawafil not after the compulsory Salat but before it
Narrated Ibn Abu Laila:
حَدَّثَنَا حَفْصُ بْنُ عُمَرَ ، قَالَ حَدَّثَنَا شُعْبَةُ ، عَنْ عَمْرٍو ، عَنِ ابْنِ أَبِي لَيْلَى ، قَالَ مَا أَنْبَأَ أَحَدٌ، أَنَّهُ رَأَى النَّبِيَّ صلى الله عليه وسلم صَلَّى الضُّحَى غَيْرُ أُمِّ هَانِئٍ ذَكَرَتْ أَنَّ النَّبِيَّ صلى الله عليه وسلم يَوْمَ فَتْحِ مَكَّةَ اغْتَسَلَ فِي بَيْتِهَا، فَصَلَّى ثَمَانِ رَكَعَاتٍ، فَمَا رَأَيْتُهُ صَلَّى صَلاَةً أَخَفَّ مِنْهَا، غَيْرَ أَنَّهُ يُتِمُّ الرُّكُوعَ وَالسُّجُودَ.
Only Um Hani told us that she had seen the Prophet (p.b.u.h) offering the Duha (forenoon prayer). She said, "On the day of the conquest of Mecca, the Prophet (ﷺ) took a bath in my house and offered eight rak`at. I never saw him praying such a light prayer but he performed perfect prostration and bowing.