The ruling on one who did not form the intention to fast and then it became clear that Ramadan had entered

The questioner : The questioner says: A man did not know that the month of Ramadan had entered this year until he saw the large number of people praying the Fajr prayer. After the prayer, he asked what the news was, and he was informed that the month had entered. Does he have to make up the fast because he did not form the intention the night before? And if he had intended that if tomorrow is from Ramadan, he would fast, what is required of him? May Allah reward you with good.

The Shaykh : If he was sleeping expecting that tomorrow might be Ramadan, and he intended in his heart that he was fasting, provided it was not clear that tomorrow was from Sha'ban, then his fast is valid and there is no doubt in it. Note the differences, because they are subtle. If he said, "I am fasting tomorrow, unless it is from Sha'ban," then he has affirmed the intention. If he said, "If tomorrow is from Ramadan, then I am fasting," then he has made the intention conditional. If he did not intend either of these, and he was not aware that it was Ramadan, and then it became clear to him, as the questioner said, when he saw many people in the Fajr prayer and they told him that Ramadan had entered, and he formed the intention as soon as he knew, then this differs from the two previous cases. All three of these cases, according to the Shaykh al-Islam, do not require making up the fast, meaning that his fast is valid and he does not have to make it up. May Allah have mercy on him, he cited as evidence for this the saying of Allah the Exalted: And he said that this person is ignorant, so he is not held accountable.
Perhaps an objection would be raised regarding the third case, where he slept without intending to fast. Perhaps it would be said that he did not form the intention. He answered, may Allah have mercy on him, by saying that the intention follows knowledge. It is not possible to form the intention before one knows, and he formed the intention as soon as he knew.
So his fast is valid. Whoever follows the opinion of the Shaykh al-Islam in this issue has done nothing wrong, and whoever makes up the fast as a precaution due to the opinion of the other scholars has done nothing wrong.