The first is that He commanded them to pray in congregation with him during the prayer in times of fear. This proves that congregational prayer is obligatory in times of fear and, by stronger reason, that it is obligatory in times of safety.

The second is that He prescribed the prayer in times of fear in congregation and permitted within it things that are otherwise impermissible without an excuse, such as turning one’s back to the qiblah and making extensive movements. These are impermissible without an excuse by scholarly consensus. The same applies, according to the majority, to separating from the imam before the concluding salutation, and likewise to falling behind in following the imam—as the rear row delays after bowing with the imam when the enemy is in front of them.

They argue: These actions invalidate the prayer if performed without an excuse. If congregational prayer were merely recommended rather than obligatory, this would entail committing a prohibited act that invalidates the prayer and abandoning the obligatory following of the imam for the sake of something recommended—even though they could have prayed individually, each performing a complete prayer. It is therefore established that congregational prayer is obligatory.

Furthermore, Allah Most High says:

“Establish prayer, give zakah, and bow with those who bow.”

This means either performing the act together—that is, praying in congregation—or what is intended by His words:

“And be with the truthful.”

If the second meaning were intended, there would be no difference between saying, “Pray with those who pray,” “Fast with those who fast,” and “Bow with those who bow.” Yet the context indicates that bowing is specifically singled out in this regard.