Compiled by Imam Yahya ibn Sharaf al-Nawawi
وعن أبي هريرة رضي الله عنه عن النبي صلى الله عليه وسلم قال: "إذا نسي أحدكم فأكل أو شرب فليتم صومه فإنما أطعمه الله وسقاه" ((متفق عليه))
The Prophet (ﷺ) said, "If any one of you forgetfully eats or drinks (while observing fasting) he should complete his Saum (fasting), for Allah has fed him and given him to drink."[Al-Bukhari and Muslim].