Is it permissible for a woman to fast voluntarily if she has days of Ramadan to make up before she does so, and is it permissible to combine the intentions of making up and voluntary fasting in a single act?

The questioner : The second question asks: Is it permissible for one who has days of Ramadan to make up to fast voluntarily before making them up? And is it permissible to combine the intentions of making up and voluntary fasting, such as fasting the Day of 'Arafah as a make-up for a day of Ramadan and as a voluntary fast for its virtue?

The Shaykh : Voluntary fasting before making up Ramadan, if it is something attached to Ramadan, such as fasting six days of Shawwal, then it does not suffice for her. The question has become frequent in the days of Shawwal about advancing the fast of six days of Shawwal in order to catch the month before making up the missed days. It is well known that the Messenger (peace and blessings be upon him) said: He said: And one who has a make-up from Ramadan has not fasted Ramadan. Accordingly, fasting six days of Shawwal before making up Ramadan is not considered fasting six days of Shawwal, because these days must be attached to the month and after its completion. However, if the voluntary fast is other than the six days, meaning other than fasting the six days of Shawwal, then the scholars have two opinions on that. Some hold that it is not permissible for one who has a make-up from Ramadan to fast voluntarily, because the obligatory is more important, so one should start with it. Others have said that it is permissible to fast voluntarily, because the time for making up the fast is extended until there remains in Sha'ban as much as he owes. If the obligatory is extended, then the voluntary before it, meaning before performing it, is permissible, just as if one fasts a voluntary fast before the obligatory prayer while its time is ample.
In any case, even with this disagreement, starting with the obligatory is the wisdom, because the obligatory is more important, and because a person may die before making up the obligatory, in which case his conscience would be burdened with this obligatory that he delayed. As for if he wants to fast this obligatory on days on which fasting is prescribed, such as fasting the ten days of Dhul-Hijjah, fasting the Day of 'Arafah, and fasting the Day of 'Ashura, and he intends with it the obligatory, then we hope that the reward of the obligatory and the voluntary will be established for him, due to the generality of the saying of the Messenger (peace and blessings be upon him) when he was asked about fasting the Day of 'Arafah, he said: So I hope that Allah will grant him both rewards: the reward of the obligatory and the reward of the voluntary. However, it is better to allocate a day for the obligatory and another day for the voluntary.

The questioner : Yes, may Allah reward you.