The ruling on one who swears an oath in forgetfulness and it is later revealed to be contrary to the truth

The question: The listener Ali Hussein Jaber from the city of Dabba in the north sent a question, saying: If a person is asked about a matter whether he did it, and he answers with the phrase: "No, by Allah, I did not do it," and then it becomes clear to him later that he did do it, is this considered an oath?
The answer: If he was forgetful and then he remembered that he did it, it does not harm him. Allah the Exalted says: [al-Baqarah:286].
As for if he did it intentionally, he must repent and seek forgiveness, and this is an error. He must repent and seek forgiveness, and that is sufficient because it is a false oath. So he must repent, and praise be to Allah. If he says: "By Allah, I did not do this," and he did do it, this is a lie and is not permissible. "By Allah, I did not visit so-and-so," or "By Allah, I did not speak to so-and-so," and he did speak to him, but he did not want to tell the person who asked him. In that case, he must repent to Allah, and he does not owe an expiation for an oath; because this is a lie, and its falsehood is greater and its evil is greater. The expiation is only for a future oath, like "By Allah, I will not do such-and-such," or "By Allah, I will certainly do such-and-such." If he fails to keep it, he owes an expiation for an oath. As for the past, it is considered a grave oath, a false oath, and it has no expiation except repentance. But if he was forgetful, he owes nothing. Yes.
The presenter: May Allah reward you with good.