Sahih Bukhari Volume 008, Book 075, Hadith Number 317B.

Narated By Anas : That the Prophet said, "For every prophet there is an invocation that surely will be responded by Allah," (or said), "For every prophet there was an invocation with which he appealed to Allah, and his invocation was accepted (in his lifetime), but I kept my (this special) invocation to intercede for my followers on the Day of Resurrection."