Sunan an-Nasa'i 2363
سنن النسائي#2363Sahihأَخْبَرَنَا أَحْمَدُ بْنُ سُلَيْمَانَ، قَالَ حَدَّثَنَا أَبُو دَاوُدَ، عَنْ سُفْيَانَ، عَنْ مَنْصُورٍ، عَنْ خَالِدِ بْنِ سَعْدٍ، عَنْ عَائِشَةَ، قَالَتْ كَانَ رَسُولُ اللَّهِ صلى الله عليه وسلم يَتَحَرَّى يَوْمَ الاِثْنَيْنِ وَالْخَمِيسِ .
It was narrated that 'Aishah said:"The Messenger of Allah used to be keen to fast on Mondays and Thursday
Scholarly Authentication
The label above is the grade most of these scholars gave — one dissenting opinion no longer speaks for all of them. If any scholar calls a narration fabricated, that verdict is shown instead, whatever the others say. Each scholar's own wording:
Abu GhuddahSahih
Al-AlbaniSahih
Zubair Ali ZaiSahih
In-book reference: 22:274