Is one who prayed Maghrib, then heard the ‘Isha’adhan before completing the first rak‘ah, and was not sure whether the time for ‘Isha’ had begun, then it became clear to him that the first muezzin was more accurate, sinful and considered to have taken the prayer out of its time, and is his action considered an act of disbelief according to those who deem one who intentionally takes a single prayer out of its time to be a disbeliever?

If a person delays prayer due to a legitimate Sharia-compliant excuse, there is no sin upon him. However, if he delays it out of negligence and without an excuse, he is sinful. Some scholars have held that delaying the Maghrib prayer after its time has passed causes it to enter the time of necessity (ḍarūrah). Scholars have differed on defining the time of choice (ikhtiyār) and necessity, and by what means a prayer is considered performed (adāʾan). As for those who assert the disbelief of one who abandons prayer, they refer to someone who abandons it intentionally, but they differ on whether he disbelieves by abandoning a single prayer absolutely, or by abandoning a prayer that is not combined with another. According to the latter opinion, one who delays the Maghrib prayer until the time for the Isha prayer exits is not deemed a disbeliever. They also differed on whether killing him is a legal punishment (ḥadd) or due to disbelief. According to some scholars, prayer is considered performed if the opening takbir (takbīrat al-iḥrām) is uttered within its prescribed time, and thus, this person's prayer would be considered performed, even if he sinned by delaying it without an excuse.