Sahih Bukhari
One-fifth of Booty to the Cause of Allah (Khumus)
Volume: 004 / Book Number: 053 / Hadith Number: 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.