Hazrat Abbas (R) reports that Nabi (Sallallahu Alaihi Wasallam) said, whoever recites:
جَزَى اللهُ عَنَّا مُحَمَّدًا صَلَّى اللهُ عَلَيْهِ وَسَلَّمَ بِمَا هُوَ أَهْلُهُ
“May Allah reward Muhammad r on our behalf such a reward that is due to him”
Then indeed it will tire 70 Angels for 1000 days (to record the reward) (Tabarani)

