It was
narrated from Abu Hurairah that the Messenger of Allah (ﷺ)
said:
"Whoever eats out of forgetfulness while fasting, let him
complete his fast, for it is Allah Who has fed him and given him to
drink." (ES)
English reference (ES): Vol. 1, Book 7, Hadith 1673 (ES)
Arabic reference (ES): Book 7, Hadith 1743 (ES)