The reason this view is correct is that what came before the omitted act was validly performed in its proper place, so there is no basis for deeming it invalid. As for what follows the omitted act, we say that it must be repeated only in order to preserve the proper sequence.

Thus, the author’s discussion of omitting a pillar—other than the opening takbīr—falls into three cases:

As for the opening takbīr, the prayer is not validly commenced if it is omitted.

The first case: he remembers it before beginning the recitation of the following rak'ah. In this case, he must go back, perform it and everything that follows it, and continue his prayer.

The second case: he does not realize it until after the salām. It is then treated as though he had omitted an entire rak'ah.

The third case: he realizes it after beginning the recitation of the following rak'ah. The rak'ah in which he omitted it is invalidated, and the second rak'ah takes its place.

According to the preferred view, however, if he omits a pillar, there are three possible cases:

The first case: if he remembers it before reaching the place where it is due, he must go back.

The second case: if he remembers it after reaching the place where it is due, he does not go back, because returning would achieve nothing; rather, the second rak'ah takes the place of the one before it.

The third case: if he remembers it after the salām, then if it was from a rak'ah other than the final one, he performs a complete rak'ah; but if it was from the final rak'ah, he performs it and whatever follows it.