Sahih Muslim , Book 31, Hadith 5974 (USC-MSA) ⓘ
'A'isha reported: Never did I feel jealous of any wife amongst the wives of Allah's Apostle as I feel in case of Khadija (though I had never seen her), for he praised her very often.
حَدَّثَنَا عَبْدُ بْنُ حُمَيْدٍ، أَخْبَرَنَا عَبْدُ الرَّزَّاقِ، أَخْبَرَنَا مَعْمَرٌ، عَنِ الزُّهْرِيِّ، عَنْ عُرْوَةَ، عَنْ عَائِشَةَ، قَالَتْ مَا غِرْتُ لِلنَّبِيِّ صلى الله عليه وسلم عَلَى امْرَأَةٍ مِنْ نِسَائِهِ مَا غِرْتُ عَلَى خَدِيجَةَ لِكَثْرَةِ ذِكْرِهِ إِيَّاهَا وَمَا رَأَيْتُهَا قَطُّ .
also referenced under: Book 44, Hadith 110 (In-Book) & Hadith 2435 (Reference)