One-fifth of Booty to the Cause of Allah (Khumus)

Bukhari :: Book 4 :: Volume 53 :: Hadith 399

Narrated ' Abdullah bin 'Abbas:

That Abu Sufyan bin Harb Informed him that Heraclius called him and the members of a caravan from Quraish who had gone to Sham as traders, during the truce which Allah's Apostle had concluded with Abu Sufyan and the Quraish infidels.