The Ruling on Forming the Intention the Night Before for Obligatory and Voluntary Fasting

Question: What is the ruling for one who did not know that the month of Ramadan had begun until after the dawn had appeared? How should he act?

Answer: One who did not know that the month of Ramadan had begun until after the dawn had appeared must abstain from things that break the fast for the rest of his day; because it is a day of Ramadan, and it is not permissible for a resident who is healthy to consume anything that breaks the fast in it. He must make up the fast because he did not form the intention to fast before the dawn. It is established from the Prophet (peace and blessings be upon him) that he said: Al-Daraqutni narrated it in his chain from 'Ummarah from 'A'ishah (may Allah be pleased with her), and he said: "The narrators in its chain are all trustworthy." Al-Muqaffi Ibn Qudamah (may Allah have mercy on him) transmitted it in al-Mughni, and it is the opinion of the majority of jurists. This refers to obligatory fasting, due to the noble hadith we mentioned. As for voluntary fasting, it is permissible during the day if one has not consumed anything that breaks the fast after the dawn; because it is authentic from the Prophet (peace and blessings be upon him) what indicates this.
We ask Allah to guide us and all Muslims to what pleases Him, and to accept their fasting and standing in prayer, for He is All-Hearing, Near. And may Allah send prayers and blessings upon our Prophet Muhammad, his family, and his Companions.