Allamah Muhammad ibn Abdur Rahman Sakhaawi said in
“القول البديع في الصلاة على الحبيب الشفيع صلى الله عليه وسلم”:
[F] “It is narrated from Safwaan ibn Sulaim that the Nabi ﷺ said:
“When it is the day of Jumuah and the night of Jumuah, then send salaat on me in abundance.”
- Collected by Shafi’ee and it is mursal.
Imam Shafi’ee collected this hadith, however his chain is mursal. A mursal hadith is one where a Tabi’ee ascribes a statement or action to the Messenger ﷺ. Since there is a break in the link, the muhaddithun grade it as weak. However, great scholars including Abu Hanifah, Malik, Ahmed and Abu Dawud consider the mursal hadith as an authentic source. Imam Shafi’ee and other muhaddithun also use the mursal hadith when it is supported. There are many other narrations which substantiates the istihbaab (desirability) of sending abundant salawaat to the Messenger ﷺ on Fridays. One authentic narration will be mentioned in the conclusion, in sha Allah. By that narration this one will become sound.