٩ـ مُحَمَّدُ بْنُ يَحْيَى عَنْ أَحْمَدَ بْنِ مُحَمَّدٍ عَنِ ابْنِ فَضَّالٍ عَنِ ابْنِ بُكَيْرٍ عَنْ عُبَيْدِ الله الْحَلَبِيِّ قَالَ سَأَلْتُ أَبَا عَبْدِ الله (عَلَيْهِ الْسَّلام) عَنِ السَّهْوِ فَإِنَّهُ يَكْثُرُ عَلَيَّ فَقَالَ أَدْرِجْ صَلاَتَكَ إِدْرَاجاً قُلْتُ فَأَيُّ شَيْ‏ءٍ الإِدْرَاجُ قَالَ ثَلاَثُ تَسْبِيحَاتٍ فِي الرُّكُوعِ وَالسُّجُودِ وَرَوَى أَنَّهُ إِذَا سَهَا فِي النَّافِلَةِ بَنَى عَلَى الأقَلِّ. فَجَمِيعُ مَوَاضِعِ السَّهْوِ الَّتِي قَدْ ذَكَرْنَا فِيهَا الأثَرَ سَبْعَةَ عَشَرَ مَوْضِعاً سَبْعَةٌ مِنْهَا يَجِبُ عَلَى السَّاهِي فِيهَا إِعَادَةُ الصَّلاَةِ الَّذِي يَنْسَى تَكْبِيرَةَ الافْتِتَاحِ وَلاَ يَذْكُرُهَا حَتَّى يَرْكَعَ وَالَّذِي يَنْسَى رُكُوعَهُ وَسُجُودَهُ وَالَّذِي لاَ يَدْرِي رَكْعَةً صَلَّى أَمْ رَكْعَتَيْنِ وَالَّذِي يَسْهُو فِي الْمَغْرِبِ وَالْفَجْرِ وَالَّذِي يَزِيدُ فِي صَلاَتِهِ وَالَّذِي لاَ يَدْرِي زَادَ أَوْ نَقَصَ وَلاَ يَقَعُ وَهْمُهُ عَلَى شَيْ‏ءٍ وَالَّذِي يَنْصَرِفُ عَنِ الصَّلاَةِ بِكُلِّيَّتِهِ قَبْلَ أَنْ يُتِمَّهَا وَمِنْهَا مَوَاضِعُ لاَ يَجِبُ فِيهَا إِعَادَةُ الصَّلاَةِ وَيَجِبُ فِيهَا سَجْدَتَا السَّهْوِ الَّذِي يَسْهُو فَيُسَلِّمُ فِي الرَّكْعَتَيْنِ ثُمَّ يَتَكَلَّمُ مِنْ غَيْرِ أَنْ يُحَوِّلَ وَجْهَهُ وَيَنْصَرِفَ عَنِ الْقِبْلَةِ فَعَلَيْهِ أَنْ يُتِمَّ صَلاَتَهُ ثُمَّ يَسْجُدَ سَجْدَتَيِ السَّهْوِ وَالَّذِي يَنْسَى تَشَهُّدَهُ وَلاَ يَجْلِسُ فِي الرَّكْعَتَيْنِ وَفَاتَهُ ذَلِكَ حَتَّى يَرْكَعَ فِي الثَّالِثَةِ فَعَلَيْهِ سَجْدَتَا السَّهْوِ وَقَضَاءُ تَشَهُّدِهِ إِذَا فَرَغَ مِنْ صَلاَتِهِ وَالَّذِي لاَ يَدْرِي أَرْبَعاً صَلَّى أَوْ خَمْساً عَلَيْهِ سَجْدَتَا السَّهْوِ وَالَّذِي يَسْهُو فِي بَعْضِ صَلاَتِهِ فَيَتَكَلَّمُ بِكَلاَمٍ لاَ يَنْبَغِي لَهُ مِثْلِ أَمْرٍ وَنَهْيٍ مِنْ غَيْرِ تَعَمُّدٍ فَعَلَيْهِ سَجْدَتَا السَّهْوِ فَهَذِهِ أَرْبَعَةُ مَوَاضِعَ يَجِبُ فِيهَا سَجْدَتَا السَّهْوِ وَمِنْهَا مَوَاضِعُ لاَ يَجِبُ فِيهَا إِعَادَةُ الصَّلاَةِ وَلاَ سَجْدَتَا السَّهْوِ الَّذِي يُدْرِكُ سَهْوَهُ قَبْلَ أَنْ يَفُوتَهُ مِثْلُ الَّذِي يَحْتَاجُ أَنْ يَقُومَ فَيَجْلِسُ أَوْ يَحْتَاجُ أَنْ يَجْلِسَ فَيَقُومُ ثُمَّ يَذْكُرُ ذَلِكَ قَبْلَ أَنْ يَدْخُلَ فِي حَالَةٍ أُخْرَى فَيَقْضِيهِ لاَ سَهْوَ عَلَيْهِ وَالَّذِي يُسَلِّمُ فِي الرَّكْعَتَيْنِ الأوَّلَتَيْنِ ثُمَّ يَذْكُرُ فَيُتِمُّ قَبْلَ أَنْ يَتَكَلَّمَ فَلاَ سَهْوَ عَلَيْهِ وَلاَ سَهْوَ عَلَى الإِمَامِ إِذَا حَفِظَ عَلَيْهِ مَنْ خَلْفَهُ وَلاَ سَهْوَ عَلَى مَنْ خَلْفَ الإِمَامِ وَلاَ سَهْوَ فِي سَهْوٍ وَلاَ سَهْوَ فِي نَافِلَةٍ وَلاَ إِعَادَةَ فِي نَافِلَةٍ فَهَذِهِ سِتَّةُ مَوَاضِعَ لاَ يَجِبُ فِيهَا إِعَادَةُ الصَّلاَةِ وَلاَ سَجْدَتَا السَّهْوِ وَأَمَّا الَّذِي يَشُكُّ فِي تَكْبِيرَةِ الافْتِتَاحِ وَلاَ يَدْرِي كَبَّرَ أَمْ لَمْ يُكَبِّرْ فَعَلَيْهِ أَنْ يُكَبِّرَ مَتَى مَا ذَكَرَ قَبْلَ أَنْ يَرْكَعَ ثُمَّ يَقْرَأَ ثُمَّ يَرْكَعَ وَإِنْ شَكَّ وَهُوَ رَاكِعٌ فَلَمْ يَدْرِ كَبَّرَ أَوْ لَمْ يُكَبِّرْ تَكْبِيرَةَ الافْتِتَاحِ مَضَى فِي صَلاَتِهِ وَلاَ شَيْ‏ءَ عَلَيْهِ فَإِنِ اسْتَيْقَنَ أَنَّهُ لَمْ يُكَبِّرْ أَعَادَ الصَّلاَةَ حِينَئِذٍ فَإِنْ شَكَّ وَهُوَ قَائِمٌ فَلَمْ يَدْرِ أَ رَكَعَ أَمْ لَمْ يَرْكَعْ فَلْيَرْكَعْ حَتَّى يَكُونَ عَلَى يَقِينٍ مِنْ رُكُوعِهِ فَإِنْ رَكَعَ ثُمَّ ذَكَرَ أَنَّهُ قَدْ كَانَ رَكَعَ فَلْيُرْسِلْ نَفْسَهُ إِلَى السُّجُودِ مِنْ غَيْرِ أَنْ يَرْفَعَ رَأْسَهُ مِنَ الرُّكُوعِ فِي الرُّكُوعِ فَإِنْ مَضَى وَرَفَعَ رَأْسَهُ مِنَ الرُّكُوعِ ثُمَّ ذَكَرَ أَنَّهُ قَدْ كَانَ رَكَعَ فَعَلَيْهِ أَنْ يُعِيدَ الصَّلاَةَ لأَنَّهُ قَدْ زَادَ فِي صَلاَتِهِ رَكْعَةً فَإِنْ سَجَدَ ثُمَّ شَكَّ فَلَمْ يَدْرِ أَ رَكَعَ أَمْ لَمْ يَرْكَعْ فَعَلَيْهِ أَنْ يَمْضِيَ فِي صَلاَتِهِ وَلاَ شَيْ‏ءَ عَلَيْهِ فِي شَكِّهِ إِلاَّ أَنْ يَسْتَيْقِنَ أَنَّهُ لَمْ يَكُنْ رَكَعَ فَإِنِ اسْتَيْقَنَ ذَلِكَ فَعَلَيْهِ أَنْ يَسْتَقْبِلَ الصَّلاَةَ فَإِنْ سَجَدَ وَلَمْ يَدْرِ أَ سَجَدَ سَجْدَتَيْنِ أَمْ سَجْدَةً فَعَلَيْهِ أَنْ يَسْجُدَ أُخْرَى حَتَّى يَكُونَ عَلَى يَقِينٍ مِنَ السَّجْدَتَيْنِ فَإِنْ سَجَدَ ثُمَّ ذَكَرَ أَنَّهُ قَدْ كَانَ سَجَدَ سَجْدَتَيْنِ فَعَلَيْهِ أَنْ يُعِيدَ الصَّلاَةَ لأَنَّهُ قَدْ زَادَ فِي صَلاَتِهِ سَجْدَةً فَإِنْ شَكَّ بَعْدَ مَا قَامَ فَلَمْ يَدْرِ أَ كَانَ سَجَدَ سَجْدَةً أَوْ سَجْدَتَيْنِ فَعَلَيْهِ أَنْ يَمْضِيَ فِي صَلاَتِهِ وَلاَ شَيْ‏ءَ عَلَيْهِ وَإِنِ اسْتَيْقَنَ أَنَّهُ لَمْ يَسْجُدْ إِلاَّ وَاحِدَةً فَعَلَيْهِ أَنْ يَنْحَطَّ فَيَسْجُدَ أُخْرَى وَلاَ شَيْ‏ءَ عَلَيْهِ وَإِنْ كَانَ قَدْ قَرَأَ ثُمَّ ذَكَرَ أَنَّهُ لَمْ يَكُنْ سَجَدَ إِلاَّ وَاحِدَةً فَعَلَيْهِ أَنْ يَسْجُدَ أُخْرَى ثُمَّ يَقُومَ فَيَقْرَأَ وَيَرْكَعَ وَلاَ شَيْ‏ءَ عَلَيْهِ وَإِنْ رَكَعَ فَاسْتَيْقَنَ أَنَّهُ لَمْ يَكُنْ سَجَدَ إِلاَّ سَجْدَةً أَوْ لَمْ يَسْجُدْ شَيْئاً فَعَلَيْهِ إِعَادَةُ الصَّلاَةِ. السَّهْوُ فِي التَّشَهُّدِ. وَإِنْ سَهَا فَقَامَ مِنْ قَبْلِ أَنْ يَتَشَهَّدَ فِي الرَّكْعَتَيْنِ فَعَلَيْهِ أَنْ يَجْلِسَ وَيَتَشَهَّدَ مَا لَمْ يَرْكَعْ ثُمَّ يَقُومَ فَيَمْضِيَ فِي صَلاَتِهِ وَلاَ شَيْ‏ءَ عَلَيْهِ وَإِنْ كَانَ قَدْ رَكَعَ وَعَلِمَ أَنَّهُ لَمْ يَكُنْ تَشَهَّدَ مَضَى فِي صَلاَتِهِ فَإِذَا فَرَغَ مِنْهَا سَجَدَ سَجْدَتَيِ السَّهْوِ وَلَيْسَ عَلَيْهِ فِي حَالِ الشَّكِّ شَيْ‏ءٌ مَا لَمْ يَسْتَيْقِنْ. السَّهْوُ فِي اثْنَتَيْنِ وَأَرْبَعٍ. إِنْ شَكَّ فَلَمْ يَدْرِ اثْنَتَيْنِ صَلَّى أَوْ أَرْبَعاً فَإِنْ ذَهَبَ وَهْمُهُ إِلَى الأرْبَعِ سَلَّمَ وَلاَ شَيْ‏ءَ عَلَيْهِ وَإِنْ ذَهَبَ وَهْمُهُ إِلَى أَنَّهُ قَدْ صَلَّى رَكْعَتَيْنِ صَلَّى أُخْرَيَيْنِ وَلاَ شَيْ‏ءَ عَلَيْهِ فَإِنِ اسْتَوَى وَهْمُهُ سَلَّمَ ثُمَّ صَلَّى رَكْعَتَيْنِ قَائِماً بِفَاتِحَةِ الْكِتَابِ فَإِنْ كَانَ صَلَّى رَكْعَتَيْنِ كَانَتَا هَاتَانِ الرَّكْعَتَانِ تَمَامَ الأرْبَعَةِ وَإِنْ كَانَ صَلَّى أَرْبَعاً كَانَتَا هَاتَانِ نَافِلَةً. السَّهْوُ فِي اثْنَتَيْنِ وَثَلاَثٍ. فَإِنْ شَكَّ فَلَمْ يَدْرِ أَ رَكْعَتَيْنِ صَلَّى أَمْ ثَلاَثاً فَذَهَبَ وَهْمُهُ إِلَى الرَّكْعَتَيْنِ فَعَلَيْهِ أَنْ يُصَلِّيَ أُخْرَيَيْنِ وَلاَ شَيْ‏ءَ عَلَيْهِ وَإِنْ ذَهَبَ وَهْمُهُ إِلَى الثَّلاَثِ فَعَلَيْهِ أَنْ يُصَلِّيَ رَكْعَةً وَاحِدَةً وَلاَ شَيْ‏ءَ عَلَيْهِ وَإِنِ اسْتَوَى وَهْمُهُ وَهُوَ مُسْتَيْقِنٌ فِي الرَّكْعَتَيْنِ فَعَلَيْهِ أَنْ يُصَلِّيَ رَكْعَةً وَهُوَ قَائِمٌ ثُمَّ يُسَلِّمَ وَيُصَلِّيَ رَكْعَتَيْنِ وَهُوَ قَاعِدٌ بِفَاتِحَةِ الْكِتَابِ وَإِنْ كَانَ صَلَّى رَكْعَتَيْنِ فَالَّتِي قَامَ فِيهَا قَبْلَ تَسْلِيمِهِ تَمَامُ الأرْبَعَةِ وَالرَّكْعَتَانِ اللَّتَانِ صَلاَّهُمَا وَهُوَ قَاعِدٌ مَكَانَ رَكْعَةٍ وَقَدْ تَمَّتْ صَلاَتُهُ وَإِنْ كَانَ قَدْ صَلَّى ثَلاَثاً فَالَّتِي قَامَ فِيهَا تَمَامُ الأرْبَعِ وَكَانَتِ الرَّكْعَتَانِ اللَّتَانِ صَلاَّهُمَا وَهُوَ جَالِسٌ نَافِلَةً. السَّهْوُ فِي ثَلاَثٍ وَأَرْبَعٍ. فَإِنْ شَكَّ فَلَمْ يَدْرِ أَ ثَلاَثاً صَلَّى أَمْ أَرْبَعاً فَإِنْ ذَهَبَ وَهْمُهُ إِلَى الثَّلاَثِ فَعَلَيْهِ أَنْ يُصَلِّيَ أُخْرَى ثُمَّ يُسَلِّمَ وَلاَ شَيْ‏ءَ عَلَيْهِ وَإِنْ ذَهَبَ وَهْمُهُ إِلَى الأرْبَعِ سَلَّمَ وَلاَ شَيْ‏ءَ عَلَيْهِ وَإِنِ اسْتَوَى وَهْمُهُ فِي الثَّلاَثِ وَالأرْبَعِ سَلَّمَ عَلَى حَالِ شَكِّهِ وَصَلَّى رَكْعَتَيْنِ مِنْ جُلُوسٍ بِفَاتِحَةِ الْكِتَابِ فَإِنْ كَانَ صَلَّى ثَلاَثاً كَانَتْ هَاتَانِ الرَّكْعَتَانِ بِرَكْعَةٍ تَمَامَ الأرْبَعِ وَإِنْ كَانَ صَلَّى أَرْبَعاً كَانَتْ هَاتَانِ الرَّكْعَتَانِ نَافِلَةً لَهُ. السَّهْوُ فِي أَرْبَعٍ وَخَمْسٍ. فَإِنْ شَكَّ فَلَمْ يَدْرِ أَرْبَعاً صَلَّى أَوْ خَمْساً فَإِنْ ذَهَبَ وَهْمُهُ إِلَى الأرْبَعِ سَلَّمَ وَلاَ شَيْ‏ءَ عَلَيْهِ وَإِنْ ذَهَبَ وَهْمُهُ إِلَى الْخَمْسِ أَعَادَ الصَّلاَةَ وَإِنِ اسْتَوَى وَهْمُهُ سَلَّمَ وَسَجَدَ سَجْدَتَيِ السَّهْوِ وَهُمَا الْمُرْغِمَتَانِ. 
9. Muhammad ibn Yahya has narrated from Ahmad ibn Muhammad from ibn Faddal from ibn Bukayr from ‘Ubayd Allah al-Halabiy who has said the following: “I once asked abu ‘Abd Allah , about mistakes which befall on me a great deal. He (the Imam) said, ‘Incorporate your Salah (prayer) properly.’ I then asked, ‘What is incorporating?’ He (the Imam) said, ‘It is saying three Tasbih (Allah is free of all defects) in Ruku‘ (bowing down on one’s knees) and in Sujud (prostrations).’ “It is narrated that if one makes mistakes in optional Salah (prayer) he considers it to be of the lesser side.” (The following to the next chapter seems to be like fatwa of al-Kulayni (rh) that he has summarized) “All the cases of mistakes are seventeen in number. In seven of them it is necessary to perform Salah (prayer) again. (1) One case is when one forgets the opening Takbir (Allah is great beyond description) which one does not remember until Ruku‘ (bowing down on one’s knees) (2) The second case is when one forgets Ruku‘ (bowing down on one’s knees) and Sujud (prostrations). (3) The third case is when one forgets and does not know if he has performed one or two Rak‘at. (4) The fourth case is when one forgets something in al-Maghrib and in the morning Salah (prayer). (5) It is when one increases something in his Salah (prayer). (6) It is when one does not know if he has increased or decreased and his guess does not settle anywhere. (7) It is when one moves away from Salah (prayer) before completing. “There are those conditions in which performing Salah (prayer) again is not necessary. Only two Sajdah (prostration) because of mistake is necessary. Of such cases is: (1) when one says Salam (the phrase of offering greeting of peace) in two Rak‘at then speaks before moving away his face from al- Qiblah (al-Ka‘bah). He completes his Salah (prayer), then performs two Sajdah (prostration) because of mistake. (2) One who forgets Tashahhud (testimonies of belief) and does not sit down in two Rak‘at and it is missed until Ruku‘ (bowing down on one’s knees) in the third Rak‘at. He performs two Sajdah (prostration) because of mistake and makes up for Tashahhud (testimonies of belief) which is missed. (3) One who does not know if he has performed four or five, has to perform two Sajdah (prostration) because of mistake. (4) One who by mistake speaks in his Salah (prayer) improperly, like commanding or prohibiting because of forgetfulness and not in a willful manner. He performs two Sajdah (prostration). Sajdah (prostration) is necessary in these four cases. Of such cases are where performing Salah (prayer) again is not necessary as well as Sajdah (prostration) because of mistake. (1) One is he who corrects his mistake before it is late like one who is to stand up but instead sits down or is to sit down but stands up then remembers it before entering in another condition, in such case he is to perform Qada 5 (perform a compensatory) for it. (2) Another is he who says Salam (the phrase of offering greeting of peace) in the first two Rak‘at then remembers. He completes before he speaks in which case the rules for mistake is not applicable to his case. (3) The rule for mistake does apply to the case of one behind an Imam who remembers and (4) as well as to the case of an Imam if people behind him remember. (5) The rule for mistake does not apply to mistake in a mistake. (6) The rule for does not apply to a mistake in optional Salah (prayer) and the rule for mistake does not apply to a repeat in optional Salah (prayer). These are six cases where repeat is not necessary as well as two Sajdah (prostration) because of mistake. “One who doubts about the opening Takbir (Allah is great beyond description) and does not know if he has said it or not, he is to say it when he remembers before Ruku‘, then does the recitation then Rukuk If one doubts in Ruku‘ and does not know if he has said the opening Takbir (Allah is great beyond description) or not, he continues his Salah (prayer) and he is not obligated for anything in this matter. If he becomes certain of not saying the opening Takbir (Allah is great beyond description), he performs his Salah (prayer) again. If one doubts when he is standing and he does not know if he has performed Ruku‘ or not, he performs Ruku‘ to ascertain his performing Rukuk If one performs Ruku‘, then remembers that he has already performed Ruku‘, he sends himself down to Sajdah (prostration) without raising his head from Ruku‘ in Rukuk If he continues and raises his head from Ruku‘, then remembers that he has already performed Ruku‘, he performs his Salah (prayer) again; he has increased in his Salah (prayer) one Rak’at. One who performs Sajdah (prostration) and because of doubt does not know if one has performed Ruku‘ or not, one continues his Salah (prayer) and he is not obligated for anything in this matter, because of his doubt unless one becomes certain that one has not performed Rukuk In this case one performs his Salah (prayer) again. If one performs Sajdah (prostration) and does not know if one has performed one or two Sajdah (prostration), one is to perform another Sajdah (prostration) to ascertain performing two Sajdah (prostration). If one performs Sajdah (prostration) and remembers that he has already performed two Sajdah (prostration), one is to perform his Salah (prayer) again, because of increase in his Salah (prayer) one Sajdah (prostration). If one doubts after standing and does not know if one has performed one or two Sajdah (prostration) one is to continue his Salah (prayer) and he is not obligated for anything in this matter. If one is certain that one has performed only one Sajdah (prostration), one is to perform another Sajdah (prostration) and he is not obligated for anything in this matter. If one reads Surah (chapter) then remembers that one has performed only one Sajdah (prostration), one is to perform another Sajdah (prostration), then stand up to complete the recitation and perform Ruku‘ and he is not obligated for anything in this matter. If one performs Ruku‘ and becomes certain that one has not performed any Sajdah (prostration) but only one Sajdah (prostration) or has not performed any Sajdah (prostration) at all, one is to perform Salah (prayer) again.” Mistakes in Tashahhud (testimonies of belief):“If one by mistake stands up before Tashahhud (testimonies of belief) in two Rak’ah, he is to sit down and say Tashahhud, if he has not reached in Ruku’ (bowing down on one’s knees), then stand up and continues his Salah (prayer) and he is not obligated for anything in this matter. If one has assumed Ruku’ and learns that one has not said Tashahhud, continues one’s Salah (prayer) and when one ends his Salah (prayer) performs two Sajdah (prostration) because of mistake and he is not obligated for anything in the condition of doubt as long one is not certain.” Mistakes about Two or Four Rak’ah:“One who doubts and does not know if one has performed two or four Rak’at, if one’s guess settles on four, one says Salam (the phrase of offering greeting of peace) and he is not obligated for anything in this matter. If one’s guess settles on one’s performing two Rak’ah, one performs two more Rak’ah and he is not obligated for anything in this matter if one’s guess is equal, one says Salam (the phrase of offering greeting of peace), then performs two Rak’ah in a standing position with al-Fatihah al-Kitab. If, in fact, one has performed two Rak’ah these two Rak’ah complete the four and if, in fact, one has performed four Rak’ah these two become optional Salah (prayer). Mistake about Two or Three Rak’ah “One who doubts and does not know if one has performed two or three Rak’ah and his guess settles on the side of two Rak’ah, one is to perform two more Rak’ah and he is not obligated for anything in this matter. If one’s guess settles on the side of three, one then is to perform one more Rak’ah and he is not obligated for anything in this matter. If one’s guess does not settle on either side and one is certain of performing two Rak’ah, one is to perform one Rak’ah in a standing position, then say Salam (the phrase of offering greeting of peace) and performs two Rak’ah in a sitting position with al-Fatihah al- Kitab. If one, in fact, has performed two Rak’ah, the two Rak’ah performed in a standing position before Salam (the phrase of offering greeting of peace) complete the four Rak’ah. The two Rak’ah in a sitting position are in place of one Rak’ah and his Salah (prayer) is complete. If one has performed three Rak’ah the one Rak’ah performed in a standing position completes the four Rak’ah and the two Rak’ah one has performed in a sitting position are counted as optional Salah (prayer). Mistakes about Four or Three Rak’ah “One who doubts and does not know if one has performed three or four and his guess settles on the side of three Rak’ah, one is to perform one Rak’ah, then say Salam (the phrase of offering greeting of peace) and he is not obligated for anything in this matter. If one’s guess settles on the side of four, one says Salam and he is not obligated for anything in this matter. If one’s guess settles on three and four, one says Salam with his doubtful condition and performs two Rak’ah in a sitting position with al- Fatihah al-Kitab. If one has performed three the two Rak’ah are counted as one to complete the four, and if one has performed four Rak’ah these two are counted as optional Salah (prayer) in one’s favor. Mistakes about Four or Five Rak’ah “One who doubts and does not know if one has performed four or five Rak’ah, if one’s guess settles on the side of four, one is to say Salam (the phrase of offering greeting of peace) and he is not obligated for anything in this matter. If one’s guess settles on five one performs his Salah (prayer) again. If one’s guess about both sides are equal one is to say Salam, then perform two Sajdah (prostration) because of mistake which are destroyers (of Satan). 