What is the expiation for swearing falsely by saying: "By Allah, my knowledge is your knowledge," while knowing more than the addressee? And is repentance accepted with fasting three days without feeding ten needy persons?

If the swearer is aware of the difference between his knowledge and the knowledge of the other person, then his swearing by Allah to the contrary is considered a "yamin ghamus" (a false oath taken intentionally), which cannot be expiated except by sincere repentance. Some scholars hold that both expiation and repentance are required. However, if the oath was uttered unintentionally, it is considered "laghw al-yamin" (a vain oath) and carries no consequence. Intentionally swearing falsely is the "yamin ghamus," even if it does not cause harm to anyone, and it has been mentioned in the noble Hadith alongside polytheism and murder. Sincere repentance erases what came before it, and according to the majority of scholars, there is no expiation for the repentant person other than repentance itself. However, if one performs expiation, according to some scholars, it is more cautious. The expiation consists of feeding ten needy persons, or clothing them, or freeing a slave; if one cannot do that, then fasting for three days.