Sahih al-Bukhari, Volume 6, Book 60, Hadith 310 (USC-MSA) ⓘ
Narrated Anas bin Malik: The Verse: 'But you did hide in your mind that which Allah was about to make manifest.' (33.37) was revealed concerning Zainab bint Jahsh and Zaid bin Haritha.
حَدَّثَنَا مُحَمَّدُ بْنُ عَبْدِ الرَّحِيمِ، حَدَّثَنَا مُعَلَّى بْنُ مَنْصُورٍ، عَنْ حَمَّادِ بْنِ زَيْدٍ، حَدَّثَنَا ثَابِتٌ، عَنْ أَنَسِ بْنِ مَالِكٍ ـ رضى الله عنه ـ أَنَّ هَذِهِ، الآيَةَ {وَتُخْفِي فِي نَفْسِكَ مَا اللَّهُ مُبْدِيهِ} نَزَلَتْ فِي شَأْنِ زَيْنَبَ ابْنَةِ جَحْشٍ وَزَيْدِ بْنِ حَارِثَةَ.
also referenced under: Book 65, Hadith 4787 (In-Book) & Hadith 4787 (DarusSalam)