Translation of Hadith: It has been narrated on the authority of Hadhrat Abu Talha Ansari (May Allah Ta'ala be well pleased with him), who narrates on the authority of his father that one day the Holy Prophet (Sallallahu alaihi wa sallam) came to us and happiness was evident from His blessed face. We told: O Prophet of Allah (Sallallahu alaihi wa sallam)! We see signs of happiness on your face. The Holy Prophet (Sallallahu alaihi wa sallam) said: The reason is that just now an angel came to me and said: O Personification of Praise (Sallallahu alaihi wa sallam)! Indeed your Lord says: Are you not happy with this that when any of your Ummati sends Durud on you, I will send mercy on him 10 times and if anyone sends Salaam to you, I will send Salaam on him 10 times. The Holy Prophet (Sallallahu alaihi wa sallam) said: Yes! I am happy.
Mustadrak 'Alas Sahihain, Hadith No. 3534,
Musannaf Ibn Abi Shaiba, Vol. 2, Pg. No. 398,
Sunan Kubra, Hadith No. 9888,
In M’ojam Kabeer of Imam Tabarani, the following words are added:
Translation of Hadith: If any of your Ummati sends Durud on you, I will send mercy on him 10 times, my angels will pray for his forgiveness and if anyone sends Salaam on you, then Me and my angels send Salaam on him 10 times.
It has been narrated on the authority of Hadhrat Abdullah Bin Mas‘ud:
Translation of Hadith: Indeed! There are some angels of Allah Ta'ala who roam the earth, who bring the Salaam of my Ummah to me. (Musnad Imam Ahmad Bin Hambal, Hadith No. 3484; Sunan Nasai, Hadith No. 1265; Mustadrak 'Alas Sahihain, Hadith No. 3535; Kitab Ush Shifa, Vol. 2, Pg. No. 79)
It is mentioned in another Hadith:
Translation of Hadith: It has been narrated on the authority of Hadhrat Ibn Wahb (May Allah Ta'ala be well pleased with him) that the Holy Prophet (Sallallahu alaihi wa sallam) said: Whoever sends Salaam unto me has as if freed a slave. (Kitab Ush Shifa, Vol. 2, Pg. No. 77)
It has been narrated on the authority of Hadhrat Abu Bakr Siddiq (May Allah Ta'ala be well pleased with him) that reciting Durud on the Holy Prophet (Sallallahu alaihi wa sallam) is more effective in wiping out sins than cold water is for dousing fire and sending Salaam on Him is better than freeing slaves. (Kitab Ush Shifa, Vol. 2, Pg. No. 77)