Answer
Wa `alaykum As-Salamu wa Rahmatullahi wa Barakatuh.
In the Name of Allah, Most Gracious, Most Merciful.
All praise and thanks are due to Allah, and peace and blessings be upon His Messenger.
In this fatwa:
Yes, voluntary fasting is permissible before making up missed Ramadan fasts if you are confident that you can still complete the obligatory fasts. However, if delaying missed fasts risks exceeding another Ramadan, then the obligatory fasts should be prioritized.
In responding to your question, Dr. Ali Sayyed Ahmad, Professor of Qurโanic exegesis and its sciences, Al-Azhar University, states:
It is permissible to observe voluntary fasting before making up for the missed days of Ramadan if you are pretty sure that after the voluntary fasting you will be able to observe the obligatory fasting (making up for the missed fast days).
However, if the time of observing voluntary fasting coincides with that of the obligatory one, say, for instance, you will not be able to observe voluntary fasting before another Ramadan is due, you have to observe the obligatory fasting first.
What I have just said about the permissibility of observing voluntary fasting before making up for the missed days in Ramadan is based on the opinion of scholars who maintain that it is not necessary to make up for the missed days in Ramadan in haste, that this could be done at any other days after Ramadan.
Thus, you can observe voluntary fasting as long as it does not coincide with the obligatory one.
Allah Almighty knows best.
Editorโs note: This fatwa is from Ask the Scholarโs archive and was originally published at an earlier date.