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كتاب التفسير
65  
Prophetic Commentary on the Qur'an (Tafseer of the Prophet (pbuh))
(2)
"Call them (adopted sons) by (the names of) their fathers. That is more just with Allah..." (V.33:5)
(2)
Sahih al-Bukhari 4782

Narrated `Abdullah bin `Umar:

We used not to call Zaid bin Haritha the freed slave of Allah's Messenger (ﷺ) except Zaid bin Muhammad till the Qu'anic Verse was revealed: "Call them (adopted sons) by (the names of) their fathers. That is more than just in the Sight of Allah." (33.5)

حَدَّثَنَا مُعَلَّى بْنُ أَسَدٍ، حَدَّثَنَا عَبْدُ الْعَزِيزِ بْنُ الْمُخْتَارِ، حَدَّثَنَا مُوسَى بْنُ عُقْبَةَ، قَالَ حَدَّثَنِي سَالِمٌ، عَنْ عَبْدِ اللَّهِ بْنِ عُمَرَ ـ رضى الله عنهما ـ أَنَّ زَيْدَ بْنَ حَارِثَةَ، مَوْلَى رَسُولِ اللَّهِ صلى الله عليه وسلم مَا كُنَّا نَدْعُوهُ إِلاَّ زَيْدَ ابْنَ مُحَمَّدٍ حَتَّى نَزَلَ الْقُرْآنُ ‏{‏ادْعُوهُمْ لآبَائِهِمْ هُوَ أَقْسَطُ عِنْدَ اللَّهِ‏}‏‏.‏
Reference : Sahih al-Bukhari 4782
In-book reference : Book 65, Hadith 304
USC-MSA web (English) reference : Vol. 6, Book 60, Hadith 305
  (deprecated numbering scheme)