How should a person who forgets what rak'ah he is performing in witr prayer or any other prayer complete his prayer?

Dear Brother / Sister,

First of all, the thoughts that come to your mind about performing the prayer incompletely while or after praying are delusions; do not take them into consideration. If you forget what rak'ah you are performing in the prayer, act based on your stronger estimation.  

If a person doubts whether he is performing the second or third rak'ah in witr prayer and if he is standing, he completes that rak'ah and reads qunut supplications and sits; he stands up without saluting, performs one more rak’ah, reads qunut supplications again and completes the prayer; he performs sajdah as-sahw (prostration of forgetfulness) at the end of the prayer.   

He does so when he doubts whether he is performing the second or third rak'ah. If he feels in his heart that he is performing the third rak'ah, he does not have to perform one more rak'ah. That is the preferred view.   

The writer of Bahr ar-Raiq and the writer of Fath al-Qadir states the following general rule regarding the issue:

When a person doubts about the number of rak'ahs he has performed, he has to perform sajdah as-sahw at the end of the prayer whether he prefers the fewer or the more rak'ah. However, some fiqh scholars do not adopt such a general rule.

Let us give an example:

If a person doubts whether he is performing the third or fourth rak'ah in a four-rak'ah prayer, and if he remembers that it is the third rak'ah after thinking a bit, he does not have to perform sajdah as-sahw at the end of the prayer if that thinking does not last as long as a rukn (part) of a prayer. However, if it has lasted as long as a rukn of a prayer, sajdah as-sahw becomes wajib since he has delayed a fard. 1

If a person doubts whether he is a resident or a traveler and cannot decide, he sits at the end of the second rak'ah and performs what is fard and wajib as a caution and completes his prayer. 2

If the imam doubts in the second prostration whether he is performing the third or fourth rak'ah and if he does not want to make a preference and decides to act based on the reaction of the congregation after getting up from prostration, he sits if the congregation sits after getting up from prostration and he stands up if the congregation stands up; in that case, sajdah as-sahw does not become necessary. For, the doubt has been eliminated by the act of the congregation and fard has not been delayed. 3

If the imam doubts in a prayer and completes it based on his conviction and if two reliable people tell him after the prayer how many rak'ahs he has prayed, he acts based on their statement; if he has performed the prayer incompletely, he performs the prayer again. 

However, if only one person tells the imam that he has performed three rak'ahs, the imam does not act based on his statement. For, he has made a preference in the prayer and this preference is not annulled since only one person tells him it has been wrong. 4

However, according to the narration from Imam Muhammad, if it is doubted that the person is telling the truth or not, the prayer is performed again as a caution. 5

Footnotes:

1. Al-Muhit / Radiyuddin Sarakhsi - Fatawa al-Hindiyya.
2. Tatarhaniyya - Fatawa al-Hindiyya.
3. Al-Muhit / Radiyuddin Sarakhsi.
4. Fatawa al-Hindiyya - Al-Muhit / Sarakhsi.
5. Celal Yıldırım, Kaynaklarıyla İslam Fıkhı, Uysal Kitabevi: 1/432-434.

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