When does a worshiper discontinue their prayer if another prayer is commenced: Is it at the beginning of the Iqamah, or the Imam's Takbeer, or is it permissible to complete it even if the Imam has started the prayer? And does the ruling differ between obligatory and supererogatory prayers, or if most of the obligatory prayer's rak'ahs have been completed?

One who begins prayer alone, then the congregational prayer is established, has two situations:

1. If his prayer is a supererogatory (nafl) prayer: Hanafis and Malikis: He prays two rak'ahs, then joins the congregation (with a difference among Malikis regarding the fear of missing a rak'ah). Shafi'is and Hanbalis: He completes it as two rak'ahs unless he fears missing the congregation (and the congregation is caught by joining the Imam before he gives the salutation). Zahiris: The supererogatory prayer becomes null and void as soon as the congregational prayer is established, based on the hadith: "When the iqamah for prayer is called, there is no prayer except the obligatory one."

2. If his prayer is an obligatory (fard) prayer: Hanafis: They detail whether to interrupt or complete it based on the type of prayer and the stage reached in it, while considering the merit of joining the congregation and avoiding prohibited supererogatory prayers. Malikis: He interrupts if he fears missing the first rak'ah with the Imam. Shafi'is: He converts it into a supererogatory prayer unless he has reached the third rak'ah. If he has risen for it, he completes it, then joins the congregation, unless it is a missed prayer of the same type as the congregation and its make-up is on a leisurely basis (al-tarakhi). Hanbalis and Zahiris: They do not consider interrupting an obligatory prayer; rather, the worshipper completes it.

The most preponderant view: If the worshipper is performing a supererogatory prayer, the preponderant view is that of the Zahiris, due to their adherence to the apparent meaning of the hadith: "When the iqamah for prayer is called, there is no prayer except the obligatory one," due to the generality of the negation.