Abu Dawud

812. Commentary:
➊ These hadiths establish that the Messenger of Allah (sallallahu alayhi wa sallam) recited lengthy portions (of the Qur’an) on different occasions. The imam should choose his recitation while keeping in mind the condition of his followers.
➋ The surahs from Surah Hujurat to the end of the Qur’an are referred to as “Mufassal” because of the repeated occurrence of «بسم الله» as a separator in them. From Surah «لم يكن» to the end are called “Qisar Mufassal” (the short Mufassal), from Surah Al-Buruj to «لم يكن» are called “Awsat Mufassal” (the medium Mufassal), and from Surah Hujurat to Al-Buruj are called “Tiwal Mufassal” (the long Mufassal).

Hadith Commentary:
(1)
In other narrations, it is clarified that Marwan ibn al-Hakam was the governor of Madinah at that time, and he recited Surah al-Ikhlas and Surah al-Kawthar in the Maghrib prayer.
Upon this, Zayd ibn Thabit (radi Allahu anhu) admonished him with reference to the practice of the Messenger of Allah (sallallahu alayhi wa sallam).
(Sunan al-Nasa’i, Kitab al-Salat, Hadith: 990)
In the narration, there is also explicit mention regarding the longer of the two long surahs, that it was Surah al-A’raf.
(Sunan al-Nasa’i, Kitab al-Salat, Hadith: 991)
Furthermore, the narrator has also clarified that the Messenger of Allah (sallallahu alayhi wa sallam) recited Surah al-A’raf in the first two rak‘ahs of Maghrib, meaning that he recited a portion in the first rak‘ah and a portion in the second rak‘ah.
(Sunan al-Nasa’i, Kitab al-Salat, Hadith: 992)
(2)
With respect to the length of the Qur’anic surahs, there are four categories:
* Sab‘ Tiwal:
The seven long surahs.
By this is meant the seven surahs from Surah al-Baqarah to Surah al-Tawbah.
It should be noted that, in terms of content, Surah al-Anfal and Surah al-Tawbah are counted as one.
* Mi’in:
By this is meant those surahs whose verses are at least one hundred or more.
These are from Surah Yunus to Surah Ta Ha.
* Mathani:
Those surahs whose verses are less than one hundred.
These surahs are from Surah al-Anbiya to Surah al-Fath.
* Mufassal:
By this is meant those surahs in which there is frequent separation by “Bismillah al-Rahman al-Rahim.”
These are of three types:
* Long Mufassal:
From Surah Qaf to Surah ‘Amma Yatasa’alun (al-Naba’).
* Middle Mufassal:
From Surah al-Nazi‘at to Surah al-Duha.
* Short Mufassal:
From Surah al-Inshirah to Surah al-Nas.
(al-Itqan fi ‘Ulum al-Qur’an by al-Suyuti, Section Eighteen on Compilation and Arrangement: 1/199, 203, Dar Ibn Kathir edition)
Generally, it was the noble habit of the Messenger of Allah (sallallahu alayhi wa sallam) to recite the long Mufassal surahs in Fajr prayer, the middle Mufassal in ‘Isha, and the short Mufassal in Maghrib.
As is mentioned in a hadith narrated from Abu Hurayrah (radi Allahu anhu).
(Sunan al-Nasa’i, Kitab al-Salat, Hadith: 983)
However, the imam must take care of his followers, so that his recitation does not become burdensome for them.
The Messenger of Allah (sallallahu alayhi wa sallam) has guided us in this matter in various ways.

991. Commentary: At that time, Marwan was the governor of Madinah; later, he became Amir al-Mu’minin. It appears that he would always recite very short surahs, as mentioned in Hadith number 990, although among the short mufassal surahs, there are surahs twice or even three times as long as those. These should also be recited. Thus, the objection of Zayd ibn Thabit radi Allahu anhu was to always reciting very short surahs, not to reciting the short mufassal surahs, because reciting those is Sunnah. As for the Messenger of Allah sallallahu alayhi wa sallam reciting a long surah like Surah al-A’raf in Maghrib, that was only on rare occasions.

990. Commentary: By "the two long surahs" is meant Surah Al-An'am and Surah Al-A'raf, and among them, the longer surah is Surah Al-A'raf. This surah is also called "Alif Lam Meem Sad" (Alif Lam Meem Sad) because it begins with these letters.