They say concerning this case: he must begin the prayer anew, (1) because he ended it on the basis that it was a two-rakʿah prayer. This differs from one who ends the Zuhr prayer, or a similar prayer, after two rakʿahs and then remembers: he should complete it as four rakʿahs and perform the prostration for forgetfulness, because he ended it on the basis that it was a four-rakʿah prayer.

The manner of performing ablution is that one forms the intention, then mentions the name of Allah, washes the hands three times, then rinses the mouth, …

His statement, “The manner of performing ablution”: the author, may Allah have mercy on him, presents the manner of ablution, including both what is obligatory and what is not obligatory.

His statement, “that one forms the intention”: intention is a condition, due to the Prophet’s saying, “Actions are only by intentions.” (2)

His statement, “then mentions the name of Allah”: saying Bismillah is obligatory according to the madhhab. The disagreement concerning this has previously been explained. (3)

His statement, “and washes the hands three times”: the evidence is the practice of the Prophet, for whenever he wished to perform ablution, he would wash his hands three times. (4) This is sunnah.

The reason for this is that the hands are the instrument used for ablution, so one should begin by washing them before anything else, so that they are clean.

His statement, “then rinses the mouth”: rinsing the mouth means putting water into one’s mouth and then expelling it.

Is it obligatory to circulate the water throughout the entire mouth or not?