Sunan an-Nasa'i, Book 11, Hadith 131 (In-Book) ⓘ
It was narrated from 'Abdullah that: A man came to him and said: "Last night I recited Al-Mufassal in one rak'ah." He said: "That is like reciting poetry. But the Messenger of Allah used to recite similar surahs, twenty surahs from Al-Mufassal, those that start with Ha-Mim."
أَخْبَرَنَا عَمْرُو بْنُ مَنْصُورٍ، قَالَ حَدَّثَنَا عَبْدُ اللَّهِ بْنُ رَجَاءٍ، قَالَ أَنْبَأَنَا إِسْرَائِيلُ، عَنْ أَبِي حَصِينٍ، عَنْ يَحْيَى بْنِ وَثَّابٍ، عَنْ مَسْرُوقٍ، عَنْ عَبْدِ اللَّهِ، وَأَتَاهُ، رَجُلٌ فَقَالَ إِنِّي قَرَأْتُ اللَّيْلَةَ الْمُفَصَّلَ فِي رَكْعَةٍ . فَقَالَ هَذًّا كَهَذِّ الشِّعْرِ لَكِنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم كَانَ يَقْرَأُ النَّظَائِرَ عِشْرِينَ سُورَةً مِنَ الْمُفَصَّلِ مِنْ آلِ حم .
also referenced under: Hadith 1006 (Reference) & Volume 2, Book 11, Hadith 1007 (DarusSalam)