What is the ruling on one who fasts the six days of Shawwal while having missed days to make up before he begins making them up, and if he begins fasting a day to make up from Ramadan and then wants to break it to respond to an invitation, is that valid?

The questioner : And this questioner says: What is the ruling on one who fasts the six days of Shawwal while having missed days to make up before he begins making them up, and if he begins fasting a day to make up from Ramadan and then wants to break it in order to respond to an invitation, is that valid?

The Shaykh : This question contains two parts:
The first part: If one fasts six days of Shawwal before making up the missed days, does that benefit him, and do these six days suffice for the six days of Shawwal?
And the answer is no, it does not benefit him, because the Prophet (peace and blessings be upon him) said: And it is known that if days of Ramadan remain upon a person, it is not said that he has fasted Ramadan. So if he has, for example, ten days remaining, is it said that he has fasted Ramadan? No, it is said he fasted part of Ramadan, twenty days of it. And on this basis, he should begin with making up the missed days, then fast six days of Shawwal. If he began with the six days before making up the missed days, he would not obtain the reward mentioned by the Messenger (peace and blessings be upon him), which is that As for the second part, if a person begins making up Ramadan, is it permissible for him to break it in order to respond to an invitation? The answer is no, based on a known principle, which is that beginning an obligatory act binds one to it, so it is not permissible for a person to break an obligatory act of worship in which he has begun, except for an excuse that permits breaking it. For this reason, the jurists (may Allah have mercy on them) mentioned the following phrase: "Whoever begins an obligatory act, it is forbidden for him to break it except for a legal excuse." This is general for all obligatory acts. As for voluntary acts, you have the choice; you may break them, and sometimes we even order you to break them. If you begin a voluntary prayer and the call to prayer is made, break it if you are in the first unit. But if you are in the second unit of the voluntary prayer, do not break it, but complete it lightly, due to the saying of the Prophet (peace and blessings be upon him): And his saying: So if you catch a unit of the voluntary prayer before the call to prayer is made, you have caught it, so complete it lightly. And if the call to prayer is made and you are in the first unit, break it without the closing salam, in order to enter into the obligatory prayer. Yes.