Abu Hurairah (May Allah be pleased with him) reported:
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].

وعن أبي هريرة رضي الله عنه عن النبي ﷺ قال: "إذا نسي أحدكم فأكل أو شرب فليتم صومه فإنما أطعمه الله وسقاه" ((متفق عليه))