Sunan Abi Dawud 2360
سنن أبي داود#2360SahihNarrated Ibn 'Umar:The Messenger of Allah (ﷺ) prohibited perpetual fasting. They (the people) said: You keep perpetual fasting, Messenger of Allah. He said: My position is not like that you yours. I am provided with food and drink
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Al-AlbaniSahih
Muhammad Muhyi Al-Din Abdul HamidSahih
Shuaib Al ArnautSahih
Zubair Ali ZaiSahih Bukhari (1962) Sahih Muslim (1102)
In-book reference: 14:48