Question: It is written in the book İslam Ahlakı, “If the sun rises while one is performing Salat al-Fajr, this salat will not be valid. However, if the sun sets while one is performing Salat al-Asr, this salat will be valid.” Additionally, it is written in Se’adet-i Ebediyye, “A salat, with the exception of Salat al-Fajr, is accepted as having been performed within its prescribed time if the initial takbir has been uttered, according to the Hanafi Madhhab, and if one rak’at of the salat has been completed according to the Maliki Madhhab and Shafi’i Madhhab; before the end of the prescribed time.” Why is Salat al-Fajr excluded from this ruling?
ANSWER
The following is written in fiqh books:
To exit from salat of one’s own accord is fard (obligatory) according to Imam-i A’zam. It is not fard, but wajib, according to Imam-i Abu Yusuf and Imam-i Muhammad. If one, after sitting as long as it takes one to say at-tahiyyat, deliberately does something that invalidates salat, e.g., laughing, talking, eating, drinking, one’s salat will be valid. However, if one’s wudu’ breaks involuntarily in salat after one has sat as long as it takes one to say at-tahiyyat, one has to renew wudu’ immediately, say the salam, and exit from salat of one’s own accord according to Imam-i A’zam. (Halabi)

If one’s wudu’ breaks before one says the salam in salat, one’s salat is nullified in the madhhabs of Shafi’i, Maliki, and Hanbali. If it breaks before one completes at-tahiyyat in the final rak’at, one’s salat is nullified in the Hanafi Madhhab, too. (İslam Ahlakı)

If one starts Salat al-Fajr before the sun has risen and if it rises before one completes it, one’s salat becomes null and void. However, there are disagreements among scholars as to whether the salat is valid or not if the sun has risen after one has sat as long as it takes one to say at-tahiyyat. (Al-Fiqh 'ala al-Madhahib al-Arba'ah)

If a sahib-i tartib (a person who does not have any qada salat or he/she has fewer than six qada salats), when performing salat, remembers the salat he/she missed or according to Imam-i A’zam if the sun has risen when he/she is performing Salat al-Fajr or if the time for Salat al-Asr starts when he is performing Salat al-Jumu’ah, his/her salat becomes null and void even if they occur after he/she has sat as long as it takes him/her to say at-tahiyyat or even when he/she is performing sajda as-sahw. If such a person is an imam, the salats of the jama’at becomes null and void. (Fatawa-i Hindiyya)

According to Imam- Abu Yusuf and Imam- Muhammad, one’s salat is valid if the sun rises while one is reciting salawat after at-tahiyyat.

If one’s excuse (‘udhr) stops while one is making wudu’ or performing salat and does not begin again until the end of the time for the next salat, one must reperform the wudu’ and the salat that one performed when one had the excuse. However, if it stopped after the salat had been completed, or after one has sat as long as tashahhud (in the last rak’at), one would not reperform salat. (Se’adet-i Ebediyye)

If one breaks wudu’ after having sat as long as tashahhud, one’s salat will be complete. After one has sat as long as the tashahhud, if it breaks by itself, and if one renews wudu’ at once and says the salam, which is wajib or, without renewing wudu’, if one does something invalidating salat, e.g., says the salam, one’s salat will be complete. (Se’adet-i Ebediyye)

If one, after completing the obligatory elements (arkaan) of salat, deliberately does something [after reciting at-tahiyyat] that makes one exit from salat, such as standing up, one’s salat will be valid. (Radd-ul-Mukhtar)

If one, after sitting as long as it takes one to recite at-tahiyyat, intentionally does something that is against salat, even if it may be after one has broken one’s wudu’, one’s salat will be valid because one has fulfilled the obligatory elements of salat, but one must repeat salat because saying the salam is wajib. If one’s action that is against salat occurs involuntarily before one sits as long as it takes one to say at-tahiyyat, one’s salat is nullified according to unanimity of scholars. If it occurs after sitting as long as it, one’s salat is nullified according to Imam-i A’zam, but it is valid according to Imam-i Abu Yusuf and Imam-i Muhammad. (Durr-ul-Mukhtar)

When the sun rises while one is performing Salat al-Fajr, when the time for Salat al-Asr starts while one is performing Salat al-Jumu’ah, when the excuse (‘udhr) of a person stops in salat, when the wound of a person heals and the dressing around it falls, when one, after performing salat with impurity on one’s garment, finds the thing that will remove impurity after sitting as long as tashahhud, if the time at which it is makruh to perform salat starts while one is offering a qada salat, one’s salat is invalidated in case of all these scenarios according to Imam-i A’zam, but not invalidated according to Imam-i Muhammad and Imam-i Abu Yusuf. (Durar and Ghurar)

If one, after sitting in the last rak’at for the duration during which one can recite at-tahiyyat, exits from salat of one’s own accord, one’s salat will be valid. (Durar and Ghurar)

If one, after sitting for the duration it takes to recite at-tahiyyat, laughs, one’s salat is considered finished. (Radd-ul-Mukhtar)

If the imam of a masbuq (a person who has not caught up with the imam in the first rak’at) laughs after sitting for the duration it takes to recite at-tahiyyat, the salat of the imam and those of non-masbuqs are complete. However, the salat of the masbuq is nullified because something breaking the salat has occurred before he has performed the obligatory elements of salat. (Radd-ul-Mukhtar)

If a sahib-i tartib remembers in salat that he/she has a missed (qada) salat to make up, his/her salat is nullified according to the unanimity of scholars if he/she remembers it before sitting as long as it takes to recite at-tahiyyat. It is still nullified according to Imam-i A’zam, but not nullified according to Imam-i Muhammad and Imam-i Abu Yusuf, if he/she remembers it after sitting for the duration it takes to recite at-tahiyyat but before saying the salam. (Radd-ul-Mukhtar)

To sum up, in order to follow three imams (namely, Imam-i A’zam, Imam-i Muhammad, and Imam-i Abu Yusuf) of the Hanafi Madhhab, we must exit from salat of our own free will after completing its obligatory elements. If we exit from salat without our own free will after completing its obligatory elements, our salats will be valid according to Imam-i Yusuf and Imam-i Muhammad. However, those who are in the Hanafi Madhhab but follow a ruling of the Maliki Madhhab out of necessity must follow the ruling of Imam-i A’zam as it is fard (obligatory) in the Maliki Madhhab to exit from salat of one’s own free will.