A person came to 'Abdullah b. Mas'ud and said: I recited all the mufassal surahs in one rak'ah during the night. 'Abdullah said: You must have recited hastily like the recitation of poetry. 'Abdullah said: I remember well the manner in which the Messenger of Allah ﷺ used to combine them, and he then mentioned twenty of the mufassal surahs, and (their combinations in) two in every rak'ah.
إِنِّي قَرَأْتُ الْمُفَصَّلَ اللَّيْلَةَ كُلَّهُ فِي رَكْعَةٍ فَقَالَ عَبْدُ اللَّهِ هَذًّا كَهَذِّ الشِّعْرِ فَقَالَ عَبْدُ اللَّهِ لَقَدْ عَرَفْتُ النَّظَائِرَ الَّتِي كَانَ رَسُولُ اللَّهِ ﷺ يَقْرُنُ بَيْنَهُنَّ قَالَ فَذَكَرَ عِشْرِينَ سُورَةً مِنَ الْمُفَصَّلِ سُورَتَيْنِ سُورَتَيْنِ فِي كُلِّ رَكْعَةٍ