عَن عَامِر بن رَبِيَعَة رَضِي اللهُ عَنهُ عَن النّبي صَلَّى اللهُ عَلَيهِ وَ سَلَّمَ قَالَ مَا مِن مُسلِمٍ يُصَلِّي عَلَيَّ إلَّا صَلَّتْ عَلَيه الملَائِكَةُ مَا صَلَّى عَلَيَّ فَليَقِلَّ العبدُ مِن ذَلِكَ أوِ ليُكثِر (ابن ماجة رقم 907)
Hadhrat Aamir bin Rabee’ah (Radhiallahu Anhu) reports that Rasulullah (Sallallahu Alaihi Wasallam) said: “Whoever recites durood upon me, the angels continuously send salaat upon him (i.e. make duaa for him) as long as he is engaged in durood. Therefore, it is left to one to decide whether he wishes to recite a little durood or abundant durood.
Acquiring Abundant Mercy of Allah Ta'ala
Ja’far bin Abdullah (Rahmatullahi Alaihi) relates: “On one occasion I saw Abu Zur’ah (Rahmatullahi Alaihi) (a famous scholar of Hadith) in a dream. I saw him in the heavens leading the angels in salaah. I asked him, “O Abu Zur’ah, how did you reach this high position of honour?” He replied: “With this hand of mine I have written one million ahaadith and whenever I wrote the blessed name of Rasulullah (Sallallahu Alaihi Wasallam), I also wrote salaat and salaam, and Rasulullah (Sallallahu Alaihi Wasallam) said: “Whoever recites salaat on me once, Allah Ta’ala bestows ten mercies upon him.
According to this calculation, it would mean that (through him writing the durood one million times), the mercies from Allah Ta’ala would amount to ten million upon him. One could well imagine that when only one mercy from the side of Allah Ta’ala means more than everything on earth, how fortunate will such a person be upon whom ten million mercies of Allah Ta’ala rain upon him? (Fazaail Durood)