Military Expeditions led by the Prophet (pbuh) (Al-Maghaazi)

Bukhari :: Book 5 :: Volume 59 :: Hadith 335

Narrated 'Aisha:

(the wife of the Prophet) Abu Hudhaifa, one of those who fought the battle of Badr, with Allah's Apostle adopted Salim as his son and married his niece Hind bint Al-Wahd bin 'Utba to him' and Salim was a freed slave of an Ansari woman. Allah's Apostle also adopted Zaid as his son. In the Pre-lslamic period of ignorance the custom was that, if one adopted a son, the people would call him by the name of the adopted-father whom he would inherit as well, till Allah revealed: "Call them (adopted sons) By (the names of) their fathers." (33.5)