The Ruling on Fasting the Six Days of Shawwāl After the Month of Shawwāl Has Ended

It is permissible to fast the six days of Shawwāl outside of the month of Shawwāl, even without a valid excuse. This is not an unprecedented or innovative opinion (bidʿan min al-qawl); rather, a group of jurists (fuqahāʾ) have held this view. This is because the underlying effective cause (ʿillah) in the ḥadīth is clear, which is that a good deed is rewarded tenfold:

 مَن جَآءَ بِٱلۡحَسَنَةِ فَلَهُۥ عَشۡرُ أَمۡثَالِهَاۖ 

((Whoever comes with a good deed will have ten times like it.)) [Al-Anʿām 6:160]

Thus, fasting Ramaḍān is equivalent to ten months, and the six days are equivalent to two months (since 6 × 10 = 60 days, which equals two months). As stated in the ḥadīth:

"Whoever fasts Ramaḍān and then follows it with six days of Shawwāl, it is as if he fasted for a lifetime (the entire year)."

The specific mention of "Shawwāl" in the text is simply because it immediately follows Ramaḍān; it is a co-extensive description (waṣf ṭardī) —that is not intrinsically relevant to the ruling— rather than a proper legal cause (waṣf munāsib).

(TN: Shawwāl is used here as (waṣf ṭardī) — meaning as an attribute that merely accompanies the ruling without having any intrinsic legal relevance to justify it. The cause here is fasting 6 days, added with a month - i.e. Ramaḍān making it 36 and when multipled by 10 making it one year (360 days) in reward)

In legal theory (Uṣūl al-Fiqh), (something to be a proper) legal cause (ʿillah) (for a ruling), it must be a relevant (munāsib), apparent (ẓāhir), and well-defined (munḍabiṭ) attribute.

Nevertheless, one should hasten to perform righteous deeds. It remains better and more complete to fast these six days within the month of Shawwāl itself.

[Another relevant] Legal Maxim Is: The default rule in legal rulings is that they possess a rationale (al-aṣlu fī al-aḥkāmi al-taʿlīl).

As for someone who missed the six days of Shawwāl due to a valid excuse, it is, by comparison, more appropriate (min bābi awlā) to have no issue regarding the permissibility of fasting them afterward. This is because making up (qaḍāʾ) a time-bound act of worship after its time has expired is legislated for valid excuses—assuming for the sake of argument that these six days are strictly bound to Shawwāl.

[Potential Objections and Responses]

If it is objected: This logic implies that whoever fasts Ramaḍān outside of Ramaḍān would also be credited with fasting ten months, just as fasting the six days outside of Shawwāl is credited as if they were fasted in Shawwāl, based on the common denominator (jāmiʿ) that a good deed is multiplied tenfold in both cases.

The Response:

• Fasting Ramaḍān outside of its month—except when making it up (qaḍāʾ) for someone who missed it due to an excuse—is impermissible by scholarly consensus (ijmāʿ). Conversely, there is no consensus stating that the six days are invalid if fasted outside of Shawwāl.

• A good deed multiplied tenfold for an obligatory act (farḍ) is far greater in reward than a good deed multiplied tenfold for a voluntary act (nafl). For an obligatory fast, this specific virtue can only be achieved during Ramaḍān by scholarly consensus under normal circumstances (excluding make-up fasts). As stated in the Ḥadīth Qudsī: "My servant does not draw near to Me with anything more beloved to Me than what I have obligated upon him."

• The fact that a good deed is multiplied tenfold for both obligatory and voluntary deeds does not mean they are equal in overall reward and merit. Furthermore, the restriction that the obligatory fast is invalid outside of Ramaḍān does not necessitate that the voluntary fast is invalid outside of Shawwāl; this is because the sanctity of time for fasting in Ramaḍān is paramount, whereas Shawwāl is legally equivalent to the rest of the months of the year in this regard.

If it is objected: The phrasing of the ḥadīth, "then follows it (with six days)..." (thumma atbaʿahu), dictates that the following must happen specifically within Shawwāl.

The Response:

• The term "following" (al-itbāʿ) applies (grammatically) for both to consecutive and non-consecutive observance, and it applies whether the six days are fasted in Shawwāl or after Shawwāl.

• The meaning is that he follows Ramaḍān, after breaking the fast, by fasting the six days. Since there is an interval between them—namely, the breaking of the fast on the day of ʿĪd—the expression “following it” remains valid whether the six days are fasted during Shawwāl or after it.

And Allah knows best.