I vowed to fast ten days upon my success in school twenty years ago, but I have not fasted until now, although I have fasted more voluntary fasts?

Question:
May Allah the Exalted reward you with good. This questioner says: I vowed to fast ten days upon my success in school twenty years ago, but I have not fasted until now. I fast the six days of Shawwal, the day of Ashura, and other such days. Does that suffice for the fast of the ten days, or not?

Answer:
This does not suffice. Fasting the six days of Shawwal and the recommended fasts do not suffice for the obligatory vow. You must fast the six days; they remain a debt upon you to Allah, and you are required to fulfill it. You fast the six days. If you had specified them for a particular year upon your success and delayed them until now, you fast them and expiate for the delay with the expiation of an oath. You fast and expiate for the delay with the expiation of an oath. However, if you did not specify them for a particular year or month, you fast them, and that is sufficient.