Sahih Bukhari Volume 009, Book 092, Hadith Number 431.
Hadith Section/Book: Sahih Bukhari Sahih Bukhari Book 92. Holding Fast to the Qur'an and Sunnah
Narrated By Anas bin Malik : Allah's Apostle said, "O Allah! Bestow Your Blessings on their measures, and bestow Your Blessings on their Sa' and Mudd." He meant those of the people of Medina.