Sayyiduna Abu Sa'id al-Khudri (may Allah be pleased with him) narrates that the Messenger of Allah (peace and blessings be upon him) said: "When any of you is in doubt in his prayer (about how many rak'ahs he has prayed), let him discard the doubt and build upon what is certain (that is, the lesser number). Then when he is certain of completion, let him make two prostrations. If his prayer was complete, that one rak'ah and the two prostrations will be voluntary; and if his prayer was deficient, that rak'ah will complete his prayer, and the two prostrations will be a cause of humiliation for Satan." This hadith is sahih (authentic) on the condition of Imam Muslim, but they did not record it with this wording!

Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) narrates that the Messenger of Allah (peace and blessings be upon him) said: "When any of you prays and does not know how many rak'ahs he has prayed, three or four, let him pray one (more) rak'ah, performing its bowing and prostration well, then make two prostrations (of forgetfulness)." This hadith is sahih (authentic) on the condition of the two Shaykhs (Bukhari and Muslim), but they did not record it.

Sayyiduna Abdullah bin Buhaynah (may Allah be pleased with him) narrates that in one of the prayers the Messenger of Allah (peace and blessings be upon him), leading us, stood up after two rak'ahs (instead of sitting for the tashahhud). The people drew his (peace and blessings be upon him) attention by saying Subhan Allah, but he (peace and blessings be upon him) carried on, until when he had finished the prayer and only the salam remained, he (peace and blessings be upon him), while still sitting, made two prostrations of forgetfulness before giving the salam. This detailed hadith is sahih (authentic) on the condition of the two Shaykhs (Bukhari and Muslim), but they did not record it!

It is narrated about Sayyiduna Sa'd bin Abi Waqqas (may Allah be pleased with him) that he stood up after two rak'ahs (instead of sitting for the first tashahhud). The people said Subhan Allah to draw his attention, but he remained standing upright. Then when he finished the prayer, he made the two prostrations of forgetfulness and said: Did you think that I would sit down (again upon being reminded)? I only did as I saw the Messenger of Allah (peace and blessings be upon him) doing. This hadith is sahih (authentic) on the condition of the two Shaykhs (Bukhari and Muslim), but they did not record it.

It is narrated from Sayyiduna Mu'awiyah bin Hudayj (may Allah be pleased with him): I prayed Maghrib with the Messenger of Allah (peace and blessings be upon him). He (peace and blessings be upon him) forgot and gave the salam after only two rak'ahs, then he (peace and blessings be upon him) left. A man said to him: "O Messenger of Allah! You forgot and gave the salam after two rak'ahs." So he (peace and blessings be upon him) ordered Sayyiduna Bilal (may Allah be pleased with him), who called the iqamah for the prayer, and then he (peace and blessings be upon him) completed the remaining rak'ah. I asked the people about the man who had said: O Messenger of Allah, you forgot. I was asked: Do you know him? I said: No, unless I see him. Then a man passed by me and I said: This is the man. The people said: This is Sayyiduna Talhah bin Ubaydullah (may Allah be pleased with him). This hadith has a sahih (authentic) chain, but the two Shaykhs did not record it.

It is narrated from Sayyiduna Imran bin Husayn (may Allah be pleased with him) that the Prophet (peace and blessings be upon him) recited the tashahhud in the two prostrations of forgetfulness and then gave the salam. This hadith is sahih (authentic) on the condition of the two Shaykhs (Bukhari and Muslim), but they did not record it; the two of them only agreed upon the narration of Khalid al-Hadhdha from Abu Qilabah, in which there is no mention of the tashahhud for the prostrations of forgetfulness.

It is narrated from Sayyiduna Imran bin Husayn (may Allah be pleased with him) that the Prophet (peace and blessings be upon him) led them in prayer and made an oversight in his prayer, so he (peace and blessings be upon him) performed the two prostrations of forgetfulness after giving the salam and speaking.

It is narrated from Sayyiduna Ibn Abbas (may Allah be pleased with them both) that the Prophet (peace and blessings be upon him) named the two prostrations of forgetfulness "al-Murghimatayn" (the two that humiliate and disgrace Satan). This hadith has a sahih (authentic) chain, but the two Shaykhs did not record it, and Abu Mujahid Abdullah bin Kaysan is among the trustworthy narrators whose hadith is collected among the people of Marw.

Iyad narrates that he asked Sayyiduna Abu Sa'id al-Khudri (may Allah be pleased with him): "One of us prays and does not remember how many rak'ahs he has prayed." He said that the Messenger of Allah (peace and blessings be upon him) said to us: "When one of you prays and does not remember how many rak'ahs he has prayed, let him perform two prostrations (of forgetfulness). And when Satan comes to one of you and says: 'You have broken your ablution,' let him say (in his heart): 'Kadhabta' (You have lied), unless he perceives a smell with his nose or hears a sound with his ear." This hadith is sahih (authentic) on the condition of the two Shaykhs (Bukhari and Muslim), but they did not record it.

It is narrated from Sayyiduna Abd al-Rahman bin Awf (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "Whoever makes an oversight in his prayer regarding three or four rak'ahs, let him complete it, for an addition (of a rak'ah) is better than a deficiency." This hadith is mufassar (explanatory) and has a sahih (authentic) chain, but the two Shaykhs did not record it.