Sunan an-Nasa'i 2431
سنن النسائي#2431Da'ifAbdul-Malik bin Abi Al-Minhai narrated from his father that:the Prophet commanded them to fast the three days of Al-Bid. He said: "That is (equivalent to) fasting for the whole month
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Abu GhuddahDaif
Al-AlbaniDaif
Zubair Ali ZaiDaif
In-book reference: 22:342