Ibn Taymiyyah (1), for the hadith plainly indicates this. It is a conditional statement: “Whoever catches one complete unit of prayer has caught …” Its implication is that whoever catches less than one complete unit has not caught it. Thus, if a woman begins menstruating after the time has commenced but before enough time has passed to perform one complete unit, she is not required to make up the prayer, because she did not catch one complete unit. But if she begins menstruating after enough time has passed for one complete unit, she must make it up.

It was also said that she is not required to make it up unless she begins menstruating while there remains enough time before the prayer’s time expires to perform the prayer and purify herself for it (2), because before that she is not required to perform the prayer, since its time is flexible. Likewise, if she becomes pure before the time expires but with less than enough time for one complete unit, she is not required to make up the prayer, because she did not catch one complete unit.

Other matters of catching up are likewise based on this, such as catching the congregational prayer: is the congregation caught by completing one unit, or by catching the opening takbir (3)?

The correct view is that it is not caught except by completing one unit, just as Friday prayer is unanimously not caught except by completing one unit. The same applies to the congregational prayer: it is not caught except by completing one unit.

His statement, “by the opening takbir within its time,” includes both the time of necessity and the time of choice. In our view, there is only one prayer that has two time periods: the afternoon prayer, according to the stronger view. Thus, if he catches the opening takbir before sunset, he has caught the afternoon prayer. However, it has already been mentioned that catching it depends upon completing one unit.

AND HE MUST NOT PRAY BEFORE HE DEEMS IT MORE LIKELY THAN NOT THAT ITS TIME HAS BEGUN …

His statement, “And he must not pray before he deems it more likely than not that its time has begun,” means: a person must not