Sahih al-Bukhari Hadith 5088

Abu Hudhaifa bin `Utba bin Rabi`a bin `Abdi Shams who had witnessed the battle of Badr along with the Prophet (ﷺ) adopted Salim رضی اللہ عنہ as his son, to whom he married his niece, Hind bint Al-Walid bin `Utba bin Rabi`a; and Salim رضی اللہ عنہ was the freed slave of an Ansar woman, just as the Prophet (ﷺ) had adopted Zaid as his son. It was the custom in the Pre-lslamic Period that if somebody adopted a boy, the people would call him the son of the adoptive father and he would be the latter's heir. But when Allah revealed the Divine Verses: 'Call them by (the names of) their fathers . . . your freed-slaves,' (33.5) the adopted persons were called by their fathers' names. The one whose father was not known, would be regarded as a Maula and your brother in religion. Later on Sahla bint Suhail bin `Amr Al-Quraishi Al-`Amiri رضی اللہ عنہ -- and she was the wife of Abu- Hudhaifa bin `Utba رضی اللہ عنہ --came to the Prophet (ﷺ) and said, "O Allah's Messenger (ﷺ)! We used to consider Salim رضی اللہ عنہ as our (adopted) son, and now Allah has revealed what you know (regarding adopted sons)." The sub-narrator then mentioned the rest of the narration.