Narrated AbuHurayrah:

When the Prophet (ﷺ) finished two rak'ahs of an obligatory prayer, a man asked him: Messenger of Allah, has the prayer been shortened, or have you forgotten? he replied: I did not do all that. The people said: Messenger of Allah, you did that. Therefore, he offered another two rak'ahs or prayer and …

Abu Hurairah reported; He then made two prostration on account of forgetfulness after he had given the salutation.

Ibn ‘Umar said :

The Messenger of Allah (ﷺ) led us in prayer and gave the salutation after two rakahs of prayer. He narrated this tradition like that of Ibn Sirin from Abu Hurairah. This version adds; he gave the salutation and prostrated two prostrations due to forgetfulness.

‘Imran b. Husain said :

The Messenger of Allah (ﷺ) gave the salutation at the end of three rakahs in the afternoon prayer, then went into the apartment (according to the version of maslamah). A man called al-Khirbaq who had long arms got up and said ; has the prayer been shortened, Messenger of Allah ? He came out angrily …

‘Abd Allah (b. Mas’ud) said :

The Messenger of Allah (ﷺ) prayed five rak’ahs in the noon prayer. He was asked whether the prayer had been extended. He asked what they meant by that. The people said : you prayed five rak’ahs. Then he made two prostrations after having given the salutation.

Narrated Abdullah ibn Mas'ud:

The Messenger of Allah (ﷺ) offered prayer. The version of the narrator Ibrahim goes: I do not know whether he increased or decreased (the rak'ahs of prayer). When he gave the salutation, he was asked: Has something new happened in the prayer, Messenger of Allah? He said: What is it? They said:…

‘Abd Allah (b. Mas’ud) said; The Messenger of Allah (ﷺ) led us in five rak’ahs of prayer. When he turned away (i,e, finished his prayer), the people whispered among themselves. He asked; what is the matter with you ? They said :

Messenger of Allah, has (the number of the rak’ahs of) the prayer been increased ? he said : No. they said; you have offered five rak’ahs of prayer. He then turned away and performed two prostrations, and afterwards gave the salutation. He then said : I am only a human being, I forget, as you forget…

Narrated Mu'awiyah ibn Khudayj:

One day the Messenger of Allah (ﷺ) prayed and gave the salutation while a rak'ah of the prayer remained to be offered. A man went to him and said: You forgot to offer one rak'ah of prayer. Then he returned and entered the mosque and ordered Bilal (to utter the Iqamah). He uttered the Iqamah for pray…

‘Ata’ b. Yasar said that Abu Sa’id al-Khudri reported the Messenger of Allah (ﷺ) as saying:

when one of you is in doubt about his prayer (i.e, how much he has prayed), he should throw away his doubt and base his prayer on what he is sure of. When he is sure about the completion of his prayer, he should make two prostrations (at the end of the prayer). If the prayer is complete, the additio…

Narrated Abdullah ibn Abbas:

The Prophet (ﷺ) named the two prostrations of forgetfulness disgraceful for the devil.

Narrated Ata' ibn Yasar:

The Prophet (ﷺ) said: When one of you is in doubt about his prayer, and does not know how much he has prayed, three or four rak'ahs, he should pray one (additional) rak'ah and make two prostrations while sitting before giving the salutation. If the (additional) rak'ah which he prayed is the fifth one, he will make it an even number by these two prostrations. If it is the fourth one, the two prostrations will be a disgrace for the devil.

Zaid b. Aslam reported on the authority of the chain of Malik:

The Prophet (ﷺ) said: If one of you is in doubt about his prayer, and if he is sure that he prayed three rak'ah, he should stand and complete one rak'ah along with its prostrations. Then he should sit and recite the tashahhud. When he finishes the prayer, and there remains nothing except salutation,…

AbuUbaydah reported, on the authority of his father Abdullah (ibn Mas'ud), the Messenger of Allah (ﷺ) as saying:

When you offer the prayer, and you are in doubt about the number of rak'ahs whether offered three or four, and you have prayed four rak'ahs in all probability in your opinion, you should recite tashahhud and make two prostrations while you are sitting before giving the salutation. afterwards you sho…

Narrated AbuSa'id al-Khudri:

The Prophet (ﷺ) said: When one of you prays, and he does not know whether he prayed more or less rak'ahs (than those prescribed by the Shari'ah), he should perform two prostrations while he is sitting. If the devil comes to him, and tells him (suggests him): "You have been defiled," he should say: "…

Abu Hurairah reported the Messenger of Allah (ﷺ) as saying; When one of you stands up to pray, the devil comes to him and confuses him so that he does not know how much he has prayed. If any of you has such an experience, he should perform two prostrations while he is sitting. Abu Dawud said; This tradition has been narrated in a similar manner by Ibn ‘Uyainab, Ma’mar and al-Laith.

This traditions has also been narrated by Muhammad b. Muslim al-Zuhr through a different chain of transmitters and to the same effect. This version adds; He should perform two prostrations before giving the salutation.

Narrated Abdullah ibn Ja'far:

The Prophet (ﷺ) said: Anyone who is in doubt in his prayer should make two prostrations after giving the salutation.

Narrated Abdullah ibn Buhaynah:

The Messenger of Allah (ﷺ) led us in prayer praying two rak'ahs. When he stood up and did not sit (at the end of two rak'ahs) the people stood up along with him. When he finished the prayer and we expect him to give the salutation, he said: "Allah is most great." While sitting and made two prostrations before giving the salutation. Then he gave it.

This tradition (mentioned above) has also been transmitted by al-Zuhri through a different chain of narrators to the same effect. This version adds:

Some of us recited the Tashahhud while they were standing. Abu Dawud said: Ibn-Zubair made two prostrations before giving the salutation in a similar way when he stood up at the end of two rak’ahs. This is the opinion of al-Zuhrl.

Narrated Al-Mughirah ibn Shu'bah:

The Prophet (ﷺ) said: When an imam stands up at the end of two rak'ahs , if he remembers before standing straight up, he should sit down, but if he stands straight up, he must not sit down, but perform the two prostrations of forgetfulness. Abu Dawud said: I have not narrated in this book of min…