The prostration of forgetfulness (sujood ul-sahw) is required whenever one
inadvertently adds extraneous parts or misses parts or is in doubt regarding parts of the
arkaan (essential pillars) of the prayer and/or its other requirements. The question posed
regards what to do when in doubt regarding the number of raka’aat prayed, and the
answer is covered in the following points:
First, definition of doubtfulness: when two possibilities are equally probable without
knowing or feeling one is more likely true than the other.
Second, when one doubts after performing salaam: One should disregard such doubt.
For example, take the case of one who has completed praying dhuhr then questions
after finishing the prayer, "Did I really pray four raka’aat or only three?" Such doubt
should be disregarded completely unless it is substantiated by clear and certain
indications; otherwise, it opens the door to waswasah (the whispering of Satan) and
unwarranted extraneous additions to the prayer.
Third, when one doubts during the prayer; this must fall into one of the following two
One can discern that one of the two possibilities about which one is in doubt is
more likely or more certain by virtue of one’s prevalent feeling or most likely
inclination: In this case, one should act according to his best assumption and
perform the prostration of forgetfulness after the salaam. The evidence for this
opinion is what was related by Ibn Mas’ood, may Allaah be pleased with him, that
(peace be upon him) prayed either an extraneous addition or missed
an essential part of the prayer (one of the narrators of the hadeeth was in doubt
which). After saying ‘salaam,’ it was said to him, "Oh Prophet of Allaah, has there
been a new change in [the way of performing] the prayer?" He
[would you say that]?" They responded, "You prayed in such and such manner."
So he bent his legs and faced towards the qiblah and performed two prostrations
then performed tasleem (saying ‘salaam’ to the right then the left). After facing
towards us, he said, "If something new had been introduced regarding the
prayers, I would have informed you about it. To the contrary, I am but a human
like youI forget as you forget, so if I forget, remind and inform me. If any of you
doubts during his prayer then he should try to discern the more certain and
correct case, then complete the prayer based upon it, then perform tasleem,
followed by two prostrations." (Al-Bukhari, Fath Al-Baari #401).
One cannot discern nor is there any prevalence apparent to indicate which of the
two cases is more certain: In this case, one should assume the least of the two and
continue based on this assumption, then perform the two prostrations of doubt after
tasleem. An example of this would be one who while praying the dhuhr prayer is
completely uncertain whether he has completed three or four raka’aat and cannot
determine which is more true. Thus, he would assume the lesser of the two, i.e.
three, and complete another raka’ah then sit for the tashahhud, then prostrate two
prostrations before saying "salaam." The basis for this ruling is the hadeeth related
by Abu Sa’eed Al-Khudri, may Allaah be pleased with him, in which he said: the
(peace be upon him) said, "If any of you doubts during his prayer and
he does not know how many [raka’aat] he has prayed, whether it is three or four,
then he should discard and cast away his doubt. He is to continue upon what one
is sure of [i.e. the lesser] then perform two prostrations before making tasleem. If
he ends up [in reality] praying five [raka’aat], then his prayer will be an
intercession for him; and if he ends up completely the [requisite] four [raka’aat]
then it is targheeman for shaytaan." (targheeman: i.e., a way of vexing Satan and
humiliating and debasing him, as well as rejecting him as a result of his failure to
achieve his desire of disturbing the worshipper.) (Al-Nawawi in explaining the
hadeeth from Sahih Muslim, 5/60).