"It has been narrated in the hadith by Hazrat Abdul Rahman Bin Auf (May Allah Almighty be pleased with him ) that 'One day when Prophet Muhammad (Peace Be Upon Him) left his house, i followed close behind. He went to an orchard where he offered prayers and prostrated so long that i started weeping thinking that he had expired.
The Prophet Muhammad (Peace Be Upon Him) raised his head from sijda and called me and asked what had happened to me. I told him that as he had been in sijda for a very long time, i had thought that he had expired and i won't see him again. The Prophet Muhammad (Peace Be Upon Him) said that he had prostrated himself before Allah Almighty so long as a token of thanks giving because He had granted him a reward, which was that if anyone, from his Ummah will recite Durood Sharif once,Allah Almighty will record 10 Virtues in his favour and erase 10 of his/her Sins'".