Sunan an-Nasa'i 2430
سنن النسائي#2430Da'ifIt was narrated that a man called 'Abdul-Malik narrated from his father, that:the Messenger of Allah used to enjoin (fasting) these days of Al-Bid and 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: 22:341