Sunan an-Nasa'i 2186
سنن النسائي#2186SahihIt was narrated from Jubair bin Nufair that a man asked Aishah about fasting and she said:"The Messenger of Allah used to fast all of Shaban, and he made sure to fast on Mondays and Thursdays
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Abu GhuddahSahih
Al-AlbaniSahih
Zubair Ali ZaiSahih
In-book reference: 22:97