ENOfficial
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."
Source: sunnah.com
Other translations
Arabic
حَدَّثَنَا أَبُو بَكْرِ بْنُ أَبِي شَيْبَةَ، حَدَّثَنَا أَبُو أُسَامَةَ، عَنْ عَوْفٍ، عَنْ خِلاَسٍ، وَمُحَمَّدِ بْنِ سِيرِينَ، عَنْ أَبِي هُرَيْرَةَ، قَالَ: قَالَ رَسُولُ اللَّهِ ـ صلى الله عليه وسلم ـ " مَنْ أَكَلَ نَاسِيًا وَهُوَ صَائِمٌ فَلْيُتِمَّ صَوْمَهُ فَإِنَّمَا أَطْعَمَهُ اللَّهُ وَسَقَاهُ " .
sunnah.com