The ruling on swallowing what comes up from the stomach while fasting

The questioner : A questioner says.

The Shaykh : Yes, I told you this. He says: When a person eats the pre-dawn meal and then abstains, sometimes some air comes up from his stomach, and with it comes some food, leaving a trace in the mouth. If he spits it out and removes it from his mouth, the trace remains.

The questioner : And if he swallows it, this is problematic. So what is the action in this situation?

The Shaykh : The apparent situation is clear. Sometimes a person burps, meaning he belches, and some food comes up from his stomach. We say: If it reaches the mouth, it is not permissible for you to swallow it. If you swallow it while you are aware, you have broken your fast. But spit it out. Either into a handkerchief if you have handkerchiefs, or into the edge of your garment. And if it happens that a taste remains, rinse your mouth until the taste disappears, because if you rinse once or twice, the taste will go away, and in that case, it does not harm him.
But suppose a man swallows it while not knowing that it is forbidden for him; his fast is valid. This is a rule we should adopt: whoever does any of the things that break the fast while ignorant, his fast is valid, and he owes no make-up. This is based on the saying of Allah the Exalted: And because al-Bukhari (may Allah have mercy on him) narrated from Asma bint Abi Bakr (may Allah be pleased with them both) that she said: We broke our fast , so their breaking of the fast was during the day, and the Prophet (peace and blessings be upon him) did not order them to make it up. If making it up had been obligatory, he would have ordered them to do so, and if he had ordered them to do so, it would have been transmitted to us. Since it was not transmitted, we know he did not order it, and since he did not order it, we know it is not obligatory.
Ha? It is not obligatory, and it is so. If a person eats or drinks while ignorant, thinking it is night, and it turns out to be day, his fast is valid. If he eats something thinking it does not break the fast, his fast is valid. If he gets cupped thinking that cupping does not break the fast, his fast is valid. Whoever does any of the things that break the fast while ignorant, his fast is valid, and he owes no make-up and no sin.
Just as the one who forgets is excused. If a person forgets and eats or drinks, the Prophet (peace and blessings be upon him) said: Praise be to Allah. Allah is the One who fed you and gave you drink. Praise Allah when you finish the cup of water while drinking it forgetfully, and say "Praise be to Allah," and do you say "Praise be to Allah who made me forget" or not? Because the fast is valid; it was Allah who fed him and gave him drink. This is among the blessings of Allah, Glorified and Exalted is He, upon the servants: that a thing done without intentional will is not a blame on the person. It was mentioned to me that a person in the past bought grapes for his family. He bought grapes for his family and carried them in a handkerchief, and he was fasting, so he forgot and started eating from these grapes. And people in the past were not wealthy, so it was easy for them to obtain grapes. And this person had craved the grapes greatly. When he reached his family, only one grape remained in the bunch. And he was eating it forgetfully. So when he remembered, his family told him he was not fasting. He said: If what I ate from the bunches does not break the fast, then this one does not break the fast. And he ate it. So does he break his fast now? Yes?
He breaks his fast with the grape, and the bunches he ate before do not break his fast. Why? Because he was forgetful; Allah, Mighty and Majestic, fed him. But this grape is the one that spoiled the fast. But some students told me that it does not spoil his fast based on the rule that the ignorant person is excused. This is an ignorant person who thinks the first part spoils the fast, so he ate this remaining part based on the invalidity of his fast. I think the excuse of ignorance does not apply to him, because this is a negligent man. It was obligatory for him to ask, and not everyone we say is excused by ignorance is excused in every case. If he is negligent and the cause for seeking knowledge has arisen, he must seek knowledge until it becomes clear. Yes. No, if it passes the mouth, let it go, meaning if a person, for example, eats and the food remains in his throat, meaning it has passed the mouth, let it go, because it is in the ruling of the internal body.