Sayyiduna Abu Hurairah, may Allah be pleased with him, narrates: A man asked the Prophet Muhammad, peace and blessings be upon him: He said, "O Messenger of Allah, peace and blessings be upon him! I was fasting and then I ate and drank out of forgetfulness." So the Prophet Muhammad, peace and blessings be upon him, said: "Allah Almighty has fed you and given you drink; complete your fast."
Hadith Referenceصحیح ابن حبان / كتاب الصوم / 3522
Hadith Gradingفضيلة الشيخ الإمام محمد ناصر الدين الألبانيصحيح - «الإرواء» (4/ 86)، «صحيح أبي داود» (2075).فضيلة الشيخ العلّامة شُعيب الأرناؤوطإسناده صحيح