Sunan Abi Dawud 2361
سنن أبي داود#2361SahihNarrated Abu Sa'id al-Khudri:The Messenger of Allah (ﷺ) as saying: Do not observe perpetual fasting. If any of you wants to observe perpetual fast, he should observe it until the dawn. They (the people) asked: You observe perpetual fast ? He replied: My position is not like that of yours. There is One Who gives me to eat, and there is One who gives me to 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
Zubair Ali ZaiSahih Bukhari (1963)
In-book reference: 14:49