So I mentioned my statement to Ibn Abbas, and he said, "You have hit the mark and done well (5)." Ibn Umar, Anas, and Urwah (6) said: He begins with the Hajj of Islam, then he performs Hajj for his vow. The benefit of his vow being binding is the necessity of expiation upon failing to fulfill it, and that if he did not intend it for his vow, he would be obligated to make it up. Based on this, if his vow coincided with part of Ramadan and part of another month, either Sha'ban or Shawwal, he is obligated to fast what fell outside of Ramadan, and he completes it from Ramadan. If he said: "I have vowed to Allah to fast Ramadan," then according to the analogy of al-Khiraqi's statement, his vow is valid, and his fasting suffices for both matters, and he is obligated to pay expiation if he fails it. According to the opinion of al-Qadi, his vow is not binding. This is the school of al-Shafi'i, because his fasting cannot be for the vow, so it is like the night. Our position is that the vow is an oath, so it becomes binding in the case of something mandatory, necessitating expiation, just like an oath by Allah the Almighty.

Section: It has been narrated from Ahmad, regarding one who vows to perform Hajj in the year, while he has the Hajj of Islam upon him, that there are two narrations. One of them is that the Hajj of Islam suffices for it and for his vow; narrated by Abu Talib. The second is that his vow becomes binding, necessitating a Hajj other than the Hajj of Islam; he begins with the Hajj of Islam, then he fulfills his vow; narrated by Ibn Mansur, because they are two acts of worship necessitated by two different causes, so one does not negate the other, just as if he had vowed two Hajj pilgrimages. The basis for the first is that he vowed an act of worship at a specified time, and he performed it within it, so it resembles what if he had said: "I have vowed to Allah to fast Ramadan."

Section: If he said: "I have vowed to Allah to fast for a month," and he intended the fasting of the month of Ramadan for his vow and for Ramadan, it would not suffice him, because the month of Ramadan is mandatory by the obligation of Allah the Almighty, and his vow entails the obligation of a month, so two months become mandatory due to two causes, and one of them does not suffice for the other, just as if he had vowed to fast two months, and as if he had vowed to pray two units (rak'at), the dawn prayer (Fajr) would not suffice him for his vow and for the prayer (6) of Fajr.

1859 - Issue: He said: (And if he vows to fast on the day such-and-such person arrives, and he arrives on a day of Fitr or Adha, he shall not fast it, and he shall fast a day in its place, and he shall offer an oath expiation.)

The summary of this is that whoever vows to fast on the day such-and-such person arrives, his vow is valid. This is the opinion of Abu Hanifah,