The difference between the two cases is clear. In the first case, both Friday prayers are invalid: each invalidates the other, so neither is valid. They must therefore repeat the Friday prayer if they are able to do so; otherwise, they should pray Dhuhr. In the second case, however, one of them is valid—the one that came first—but it is unknown which one it is. Since the Friday prayer is not repeated twice, the prayer is not repeated as a Friday prayer in this instance, even if they gather in a single mosque. Rather, everyone must repeat the prayer as Dhuhr.

The minimum sunnah prayer after the Friday prayer is two rak‘ahs, and the maximum is six, ……….

His statement, “The minimum sunnah prayer after the Friday prayer is two rak‘ahs, and the maximum is six”: the author now begins to explain the voluntary prayers connected with the Friday prayer. The minimum is two rak‘ahs, because the Prophet ﷺ “would pray two rak‘ahs after the Friday prayer in his home” (1). This is authentically established from him in al-Bukhari and Muslim, on the authority of Abdullah ibn Umar, may Allah be pleased with them both.

The maximum is six, because it is reported from Abdullah ibn Umar, through a chain graded authentic by al-Iraqi (2), that the Prophet ﷺ would pray six rak‘ahs. Ibn Umar would, “after praying the Friday prayer in Mecca, go forward and pray two rak‘ahs, then pray four; while in Medina, he would pray two rak‘ahs in his home, saying: ‘The Messenger of Allah ﷺ used to do this’” (3).

As for four rak‘ahs, this is because the Prophet ﷺ commanded it, saying: “When one of you performs the Friday prayer, let him pray four rak‘ahs after it” (4).

Thus, the sunnah prayer after the Friday prayer may be two, four, or six rak‘ahs,