Fiqh-us-Sunnah, Volume 2: Prostrations of forgetfulness during the prayer
It is confirmed that the Prophet sallallahu alehi wasallam sometimes forgotsomething in the salah. It is also true that he said: "I am a human beingand forget like you forget. If I forget, remind me." There are specificpoints concerning such prostrations and they are presented below.
Volume2, Page 46a: How to perform these prostrations of forgetfulness
The "prostrations of forgetfulness" (sujjud us-sahu) are twoprostrations which a person makes before the taslim. All of this has beenconfirmed from the Prophet sallallahu alehi wasallam. In the sahih, it isrecorded from Abu Sa'id al-Khudri that the Prophet said: "If one of youhas some doubts during his salah and he does not recall (the number of rak'at)he has prayed, three or four, then he can put an end to his doubt by performingsalah according to what he was certain of [the lesser amount] and then makingtwo sujjud before the taslim." In the story of Zhul-Yadain, in the twoSahihs, we are told the Prophet sallallahu alehi wassalam made the prostrationsafter the taslim.
Ash-Shaukani says: "The best that is stated on this subject is that onemust follow what the Prophet said or did, respecting the sujjud before or afterthe taslim. If one does something that necessitates sujjud before the taslim,one should make them before the taslim, and if one does something requiringsujjud after the taslim, then one should make them after the taslim. As forthose acts of forgetfulness that are not related to any specific time eitherbefore or after the taslim, one may choose to make the prostrations before orafter the taslim in cases of addition or reduction in the salah. This is basedon what Muslim recorded in his Sahih from Ibn Mas'ud that the Prophetsallallahu alehi wasallam said: 'If one adds or decreases something from hissalah, he should make two sujjud."'
Volume2, Page 47: When to perform these prostrations of forgetfulness
The "sujjud us-sahu" are to be performed in the followingcircumstances:
-1- If a person makes the taslim before he actually completes the prayers.Ibn Sireen relates from Abu Hurairah who said: "The Prophet sallallahualehi wasallam prayed either zuhr or 'asr salah with us and he prayed only tworak'at and made the taslim. He got up and leaned against a piece of wood in themosque as if he was angry. He put his right hand on his left and interlockedhis fingers. Then, he placed his cheek on the back of his left hand. And somepeople left the mosque in a hurry. And they said: 'The prayer has beenshortened?' Among the people were Abu Bakr and 'Umar, and they were shy tospeak to him. One of the people, who was called Zhul-Yadain, said: 'O Messengerof Allah have you forgotten or has the prayer been shortened?' He answered: 'Ihave not forgotten and it has not been shortened.' Then he asked: 'Is it asZhul-Yadain has said?' The people answered in the affirmative...At that, he ledthe people in what he had ommitted and made the taslim. After which he made thetakbir and prostrated the way he usually prostrated or perhaps even longer.Next, he raised his head and made the takbir. Then, he made the takbir [again]and prostrated, like one of his customary sujjud or perhaps even longer, andfinally, he raised his head." This is related by al-Bukhari and Muslim.
'Ata' relates that Ibn az-Zubair prayed maghrib and made the taslim aftertwo rak'at and then he stood up and wanted to kiss the black stone, when thepeople tried to correct him he said: "What is the matter with you?"Then he prayed what he had left out and performed two sujjud. When this wasmentioned to Ibn 'Abbas, he said that it was not far from the sunnah of theProphet sallallahu alehi wasallam. This is related by Ahmad, al-Bazzar, andat-Tabarani.
-2- In the case of an addition to the prayer. Ibn Mas'ud narrates that theProphet prayed five rak'at and the people asked him: "Has there been anaddition to the prayer?" He asked: "Why do you say that?" Theyreplied: "You prayed five rak'at" Then he made two sujJud after hehad made the taslim. This is related by the group. This hadith proves that theprayer of one who prays five rak'at out of forgetfulness, without sittingduring the fourth rak'ah, is acceptable.
-3- In the case of forgetting the first tashahud or one of the other sunnahacts of the prayer. Ibn Buhainah narrates that the Prophet stood after tworak'at. The people tried to correct him but he continued. When he finished hissalah, he made two sujjud and made the taslim. This is related by the group.'This hadith shows that one who forgets the first sitting but is reminded of itand he recalls it before he completely stands should return and sit, but if heis already completely standing, he should not sit down. This is supported bywhat Ahmad, Abu Dawud, and Ibn Majah recorded from al-Mughirah ibn Shu'bah,that the Prophet sallallahu alehi wasallam said: "If one of you standsafter two rak'at and he has not completely stood, then he should sit. If he isalready completely standing, he should not sit and he should make two sujjud offorgetfulness."
-4- In the case of doubt over whether or not one performed some act of theprayer. 'Abdurrahman ibn 'Auf reported that he heard the Prophet say: "Ifone of you has some doubt during his salah and he does not know if he prayedone rak'ah or two, he should take it to have been just one. If he does not knowif he prayed two rak'at or three, he should take it to have been just two. Ifhe does not know if he prayed three rak'at or four, he should take it to havebeen just three. [In all such cases] at the end of his prayer, while sitting,he should make two sujjud before the taslim." This is related by Ahmad,Ibn Majah, and at-Tirmizhi. The latter grades it sahih.
In one narration, it is stated: "Whoever prays and has some doubt thathe was short of the complete prayer, he should continue praying until hesuspects that he has added something to the prayer [with respect to the numberof rak'at that he has prayed]." Abu Sa'id al-Khudri narrated that theProphet sallallahu alehi wasallam said: "If one of you has some doubtsduring his prayer and does not know if he prayed three or four [rak'at], thenhe should remove his doubt by praying according to the amount that he iscertain he had performed and then make two sujjud before the taslim. If he hadprayed five rak'at, the two sujjud would make it even. If he had prayed acomplete four rak'at [when he had finished], they would be in defiance of theSatan." This is related by Ahmad and Muslim. These two ahadith prove whatthe majority of the scholars have said, namely, if one has some doubtconcerning the number of rak'at one has prayed, one should act according to theamount that one is certain to have prayed (the lesser amount) and then make twosujjud before the taslim.