prescribed in the prayer; it resembles the prostration of the core of the prayer.

Section: If he forgets the prostration until he has started another prayer, he prostrates after finishing it, according to the apparent meaning of the words of Al-Khiraqi, because he is in the mosque. According to the opinion of others, if a long interval has passed, he does not prostrate, otherwise he does.

Section: The prostration of forgetfulness for matters whose intentional omission invalidates the prayer is mandatory. It is reported from Ahmad that it is (13) not mandatory. Perhaps the basis for this is that the mandatory acts (wajib) for which the prostration was prescribed to compensate are themselves not mandatory, so their compensation is not mandatory. This is the opinion of Al-Shafi'i and the scholars of opinion, due to the statement of the Prophet (peace and blessings of Allah be upon him): "The rak'ah and the two prostrations were a supererogatory act (nafilah) for him" (14). Our evidence is that the Prophet (peace and blessings of Allah be upon him) commanded it in the hadith of Ibn Mas'ud and Abu Sa'id, performed it, and said: "Pray as you have seen me praying" (15). His word "nafilah" means that he has a reward for it, just as he also called the rak'ah a nafilah, while it is mandatory for one who is in doubt (16) without disagreement. As for that which is prescribed (17) for things whose intentional omission does not invalidate the prayer, it is not mandatory. Ahmad said: "The prostration is only mandatory in cases reported from the Prophet (peace and blessings of Allah be upon him)." This means what is of the same significance, so we make an analogy based on the addition of a fifth [rak'ah] to all other additions of actions from the genus of the prayer, and based on the omission of the tashahhud to the omission of other mandatory acts, and based on the taslim after a deficiency to the verbal additions that invalidate [the prayer] if done intentionally.

Section: If he omits a mandatory act (wajib) intentionally, if it is before the taslim, his prayer is invalidated because he deliberately neglected a mandatory act in the prayer. If he omits a mandatory act after the taslim, his prayer is not invalidated;