Sahih Bukhari Volume 002, Book 024, Hadith Number 574A.

Narated By 'Abdullah bin Abu Aufa : Whenever a person came to the Prophet with his alms, the Prophet would say, "O Allah! Send your Blessings upon so and so." My father went to the Prophet with his alms and the Prophet said, "O Allah! Send your blessings upon the offspring of Abu Aufa."