First fast whatever Fasting that you have to make up for

Question :

Is it permissible to fast six days of Shawwal before fasting to make up for missed days of Ramadhan? Is it permissible to fast Monday during the month of Shawwal with the intention of making up for the fast of Ramadhan and with the intent of gaining the reward of fasting on Monday?

Answer:

The reward of fasting six days during the month of Shawwal cannot be achieved unless the person completed the fasting of the month of Ramadhan. Therefore, whoever has fasting to make up for from Ramadhan, he does not fast six days of Shawwal until after he makes up for the fasting of Ramadhan. This is because the Prophet said:
"Whoever fasted Ramadhan and then followed it with (fasting) six days of Shawwal..."

Based upon this we say to whoever has to make up for fasting: "First fast what you have to make up for, then fast the six days of Shawwal." If it happens that fasting these six days coincides with Monday and Thursday, then the person gets the reward of both if he has the intention for getting the reward of the six days and the intention for the reward of Monday or Thursday. This is due to the Prophet's statement:
"Actions are only with intentions, and every person will only get what he intended."
Source:
Ash-Shaykh Ibn 'Uthaimin
Fatawa Islamiyah, Vol. 3 Pages 313-314

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