Allamah Muhammad ibn Abdur Rahman Sakhaawi said in
“القول البديع في الصلاة على الحبيب الشفيع صلى الله عليه وسلم”:
[G] “It is narrated from Ali رضي الله عنه that he said, “The one who sends a hundred (100) salaat upon the Nabi ﷺ on the day of Jumuah, he will come on the Day of Judgement with such a noor (light) that if it was to be distributed amongst the creation it would encompass all of them.”
Collected by Abu Nuaim in ‘Al-Hilyah’. And he said, “Gharib.”
After narrating this hadith Abu Nu’aim said, “Gharib from the hadith of Ibrahim and Ibn A’jlaan. We did not write it but from the hadith of Muhammad ibn Ahmed Al-Bukhari.” [Hilyatul Awliyaa Vol.8 Pg.47]
Imam Baihaqi also collected this athar in his ‘Shu’abul Imaan’ with a slightly different wording and chain. Ali رضي الله عنه said, “Whoever sends salutations on the Prophet ﷺ on the the day of Jumu’ah a hundred times, he will come on the Day of Qiyamah and upon his face will be such a noor (light) that the people will ask, ‘What action did he used to do?’” [Shu’abul Imaan Vol.4 Pg.436] The editor said that there are narrators in the chain which he was unable to locate.