Sunan Abi Dawud

Narrated 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