The Prophet (ﷺ) said, "If somebody eats something forgetfully while he is fasting, then he should complete his fast, for Allah has made him eat and drink."
Sahih al-Bukhari Book 83, Hadith 47
← Previous Hadith When the pagans were defeated during the (first stage) of the battle of Uhud, Satan shouted, "O Allah's slaves! Beware of what is behind you!" So the front files of the Muslims attacked their own back files. Hudhaifa bin Al-Yaman looked and on seeing his father he shouted: "My father! My father!" By Allah! The people did not stop till they killed his father. Hudhaifa then said, "May Allah forgive you." `Urwa (the sub-narrator) added, "Hudhaifa continued asking Allah forgiveness for the killers of his father till he met Allah (till he died).

Sahih al-Bukhari Book 83, Hadith 46 Next Hadith → Once Allah's Messenger (ﷺ) led us in prayer, and after finishing the first two rak`at, got up (instead of sitting for at-Tahiyyat) and then carried on with the prayer. When he had finished his prayer, the people were waiting for him to say Taslim, but before saying Tasiim, he said Takbir and prostrated; then he raised his head, and saying Takbir, he prostrated (SAHU) and then raised his head and finished his prayer with Taslim.

Sahih al-Bukhari Book 83, Hadith 48