The Power of Durood Sharif:

The Holy Prophet (Peace & Blessings of Allah be Upon Him) Said:
"Whoever out of love & interest recites Durood Sharif upon Me 3 times during the day and 3 times during the night, Allah (Subhanahu Wa Ta'ala) will forgive the sins that he committed during that day & night."

(At'Targheeb Wat'tarheeb Vol.2 p328)