Musnad Ahmad 4127

It was narrated from ‘Amr bin Murrah that he heard Abu Wa'il narrate that A man came to Ibn Mas'ood and said: I recited all of al-Mufassal in one rak'ah. ‘Abdullah said: Is this a quick recitation like reciting poetry? I learned the pairs that the Messenger of Allah (ﷺ) used to put together. And he mentioned twenty soorahs of al-Mufassal, two soorahs, two soorahs in each rak'ah.