Sahih Bukhari Volume 004, Book 053, Hadith Number 374.
Hadith Section/Book: Sahih Bukhari Sahih Bukhari Book 53. One-Fifth Of Booty to the Cause Of Allah (Khumus)
Narated By Anas : The Prophet said, "I give to Quraish people in order to let them adhere to Islam, for they are near to their life of Ignorance (i.e. they have newly embraced Islam and it is still not strong in their hearts."