Sahih al-Bukhari 775
Narrated Abu Wa'il:
A man came to Ibn Mas`ud and said, "I recited the Mufassal (Suras) at night in one rak`a." Ibn 
Mas`ud said, "This recitation is (too quick) like the recitation of poetry. I know the identical Suras 
which the Prophet (ﷺ) used to recite in pairs." Ibn Mas`ud then mentioned 20 Mufassal Suras including 
two Suras from the family of (i.e. those verses which begin with) Ha, Meem [??] (which the Prophet (ﷺ) 
used to recite) in each rak`a.
حَدَّثَنَا آدَمُ، قَالَ حَدَّثَنَا شُعْبَةُ، عَنْ عَمْرِو بْنِ مُرَّةَ، قَالَ سَمِعْتُ أَبَا وَائِلٍ، قَالَ جَاءَ رَجُلٌ إِلَى ابْنِ مَسْعُودٍ فَقَالَ قَرَأْتُ الْمُفَصَّلَ اللَّيْلَةَ فِي رَكْعَةٍ‏.‏ فَقَالَ هَذًّا كَهَذِّ الشِّعْرِ لَقَدْ عَرَفْتُ النَّظَائِرَ الَّتِي كَانَ النَّبِيُّ صلى الله عليه وسلم يَقْرِنُ بَيْنَهُنَّ فَذَكَرَ عِشْرِينَ سُورَةً مِنَ الْمُفَصَّلِ سُورَتَيْنِ فِي كُلِّ رَكْعَةٍ‏.‏