Sunan Abi Dawud 2451
سنن أبي داود#2451HasanNarrated Hafsah, Ummul Mu'minin: The apostle of Allah (ﷺ) used to fast three days every month: Monday, Thursday and Monday in the next week
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Al-AlbaniHasan
Muhammad Muhyi Al-Din Abdul HamidHasan
Zubair Ali ZaiIsnaad Hasan
In-book reference: 14:139