The Messenger of Allah ﷺ said: When any one of you is in doubt about his prayer and he does Dot know how much he has prayed, three or four (rak'ahs). he should cast aside his doubt and base his prayer on what he is sure of. then perform two prostrations before giving salutations. If he has prayed five rak'ahs, they will make his prayer an even number for him, and if he has prayed exactly four, they will be humiliation for the devil. (Using translation from Muslim 571a)   

قَالَ رَسُولُ اللهِ ﷺ إِذَا شَكَّ أَحَدُكُمْ فِي صَلَاتِهِ فَلَمْ يَدْرِ كَمْ صَلَّى ثَلَاثًا أَمْ أَرْبَعًا فَلْيَطْرَحِ الشَّكَّ وَلْيَبْنِ عَلَى مَا اسْتَيْقَنَ وَلْيَسْجُدْ سَجْدَتَيْنِ وَهُوَ جَالِسٌ قَبْلَ أَنْ يُسَلِّمَ فَإِنْ كَانَ هِيَ خَمْسًا كَانَتَا شَفْعًا وَإِنْ صَلَّى تَمَامَ الْأَرْبَعِ كَانَتَا تَرْغِيمًا لِلشَّيْطَانِ  

[Machine] The Messenger of Allah ﷺ said: "If anyone of you has doubts about his prayer, he should not know how many times he prayed three or four (rak'ahs). He should stand up and pray a rak'ah, then prostrate twice while sitting before the salutation. If the rak'ah he prayed was the fifth, he should make up for it with these two prostrations. If it was the fourth, then the two prostrations are a deterrent for Satan, except that Hisham reported to Abu Sa'eed al-Khudri that it is done like this."  

أَنَّ رَسُولَ اللهِ ﷺ قَالَ إِذَا شَكَّ أَحَدُكُمْ فِي الصَّلَاةِ فَلَا يَدْرِي كَمْ صَلَّى ثَلَاثًا أَوْ أَرْبَعًا فَلْيَقُمْ فَلْيُصَلِّ رَكْعَةً ثُمَّ لِيَسْجُدْ سَجْدَتَيْنِ وَهُوَ جَالِسٌ قَبْلَ السَّلَامِ فَإِنْ كَانَتِ الرَّكْعَةُ الَّتِي صَلَّى خَامِسَةً شَفَعَهَا بِهَاتَيْنِ السَّجْدَتَيْنِ وَإِنْ كَانَتْ رَابِعَةً فَالسَّجْدَتَانِ تَرْغِيمٌ لِلشَّيْطَانِ إِلَّا أَنَّ هِشَامًا بَلَغَ بِهِ أَبَا سَعِيدٍ الْخُدْرِيِّ هَكَذَا  

[Machine] The Messenger of Allah ﷺ said, "If one of you is unsure whether he has prayed three or four (rak'ahs), then he should complete it and perform one more rak'ah, then make two prostrations of forgetfulness while sitting. If his prayer was five (rak'ahs), then the extra rak'ah is a voluntary prayer, and if it was four (rak'ahs), then they are a means of thwarting Satan, and this is their meaning."  

قَالَ رَسُولُ اللهِ ﷺ إِذَا لَمْ يَدْرِ أَحَدُكُمْ ثَلَاثًا صَلَّى أَمْ أَرْبَعًا؟ فَلْيُتِمَّ وَيُصَلِّي رَكْعَةً ثُمَّ يَسْجُدْ بَعْدَ ذَلِكَ سَجْدَتَيِ السَّهْوِ وَهُوَ جَالِسٌ فَإِنْ كَانَتْ صَلَاتُهُ خَمْسًا شَفَعَتْ صَلَاتَهُ وَإِنْ كَانَتْ أَرْبَعًا كَانَتَا تَرْغِيمًا لِلشَّيْطَانِ وَبِمَعْنَاهُ  

[Machine] I sat with Umar bin Al-Khattab, and he said: "O Ibn Abbas, have you heard from the Prophet ﷺ about a person who forgets their prayer and does not know whether they increased or decreased in it?" I said: "And have you heard anything about it, O Amir al-Mu'minin, from the Messenger of Allah ﷺ ?" He said: "No, by Allah, I have not heard anything from him regarding it, nor have I asked him about it. But when Abdur-Rahman bin Awf came, Umar informed him about it. And Abdur-Rahman said: 'But I have heard this from the Prophet ﷺ .' Umar said: 'Then you have the knowledge that we were seeking, so what did you hear?' Abdur-Rahman said: 'I heard the Prophet ﷺ say: If any one of you is in doubt about his prayer, then he should consider it as one unit (rak'ah) and two units (rak'ah), and if he is in doubt about two units (rak'ah) or three, then he should consider it as two units (rak'ah), and if he is in doubt about three or four, then he should consider it as three units (rak'ah), until the doubt concerning the addition is removed, and he should prostrate twice before he gives the Salam, then he should give the Salam, and this is its meaning.'"  

جَلَسْتُ إِلَى عُمَرَ بْنِ الْخَطَّابِ ؓ فَقَالَ يَا ابْنَ عَبَّاسٍ هَلْ سَمِعْتَ مِنَ النَّبِيِّ ﷺ فِي الرَّجُلِ إِذَا نَسِيَ صَلَاتَهَ فَلَمْ يَدْرِ أَزَادَ أَمْ نَقَصَ مَا أَمَرَ بِهِ فِيهِ؟ قُلْتُ وَمَا سَمِعْتَ أَنْتَ يَا أَمِيرَ الْمُؤْمِنِينِ مِنْ رَسُولِ اللهِ ﷺ شَيْئًا فِي ذَلِكَ؟ قَالَ لَا وَاللهِ مَا سَمِعْتُ مِنْهُ فِيهِ شَيْئًا وَلَا سَأَلْتُ عَنْهُ إِذْ جَاءَ عَبْدُ الرَّحْمَنِ بْنُ عَوْفٍ فَقَالَ فِيمَا أَنْتُمَا؟ فَأَخْبَرَهُ عُمَرُ فَقَالَ سَأَلْتُ هَذَا الْفَتَى عَنْ كَذَا وَكَذَا فَلَمْ أَجِدْ عِنْدَهُ عِلْمًا قَالَ عَبْدُ الرَّحْمَنِ لَكِنْ عِنْدِي لَقَدْ سَمِعْتُ ذَلِكَ مِنَ النَّبِيِّ ﷺ فَقَالَ عُمَرُ فَأَنْتَ عِنْدَنَا الْعَدْلُ الرِّضَا فَمَاذَا سَمِعْتَ؟ قَالَ سَمِعْتُ النَّبِيَّ ﷺ يَقُولُ إِذَا شَكَّ أَحَدُكُمْ فِي صَلَاتِهِ فَشَكَّ فِي الْوَاحِدَةِ وَالِثْنَتَيْنِ فَلْيَجْعَلْهُمَا وَاحِدَةً وَإِذَا شَكَّ فِي الِاثْنَتَيْنِ وَالثَّلَاثِ فَلْيَجْعَلْهَا اثْنَتَيْنِ وَإِذَا شَكَّ فِي الثَّلَاثِ وَالْأَرْبَعِ فَلْيَجْعَلْهَا ثَلَاثًا حَتَّى يَكُونَ الْوَهْمُ فِي الزِّيَادَةِ يَسْجُدُ سَجْدَتَيْنِ قَبْلَ أَنْ يُسَلِّمَ ثُمَّ يُسَلِّمُ وَبِمَعْنَاهُ  

[Machine] We were with Umar when we mentioned a man who was distracted during his prayer and did not know how much he had prayed. Umar asked, "Did you hear anything about this?" We replied, "No." Then, Abdur Rahman ibn Awf came and asked what we were discussing. We told him about the man who was distracted in his prayer and did not know how much he had prayed. Abdur Rahman ibn Awf said, "I heard the Messenger of Allah ﷺ say that if a person is distracted and does not know whether they have prayed two, three, or four units, they should consider the distraction as an addition and prostrate for two units." Muhammad ibn Ishaq said, "I met Husayn ibn Abdullah and mentioned this hadith to him. He asked if it was supported (with chains of narrators) and I said, 'No.' He then said, 'But Makhooul narrated it from Kurayb, from Ibn Abbas, from Abdur Rahman ibn Awf, from the Prophet ﷺ '." Al Muharibbi also narrated it from Muhammad ibn Ishaq, with a similar meaning as the narration of Ibn Ulayyah. This hadith has reached Husayn ibn Abdullah, who is weak in narration, except that he has a witness from the hadith of Makhooul. Abu Bakr ibn Al Harith Al Faqih informed us, who was informed by Abu Muhammad Abdullah ibn Muhammad ibn Ja'far, known as Abu Al Sheikh Al Asbahani, who was informed by Ahmad ibn Amr, meaning Ibn Abi Asim, who was informed by Sulaiman ibn Yusuf, who was informed by Abdullah ibn Waqid Al Harrani, who was informed by Abdur Rahman ibn Thabit ibn Thawban, from his father, from Makhooul. He mentioned this hadith similarly to the narration of Ibn Ishaq, from Makhooul, from Kurayb, from Ibn Abbas, from Abdur Rahman ibn Awf, from the Prophet ﷺ . It is also narrated from a different chain through Ibn Abbas.  

كُنَّا عِنْدَ عُمَرَ فَتَذَاكَرْنَا الرَّجُلَ يَسْهُو فِي صَلَاتِهِ فَلَمْ يَدْرِ كَمْ صَلَّى قَالَ فَقُلْتُ مَا سَمِعْتُ فِي ذَلِكَ شَيْئًا؟ قَالَ فَبَيْنَا نَحْنُ كَذَلِكَ إِذْ جَاءَ عَبْدُ الرَّحْمَنِ بْنُ عَوْفٍ فَقَالَ فِيمَ أَنْتُمْ؟ قُلْنَا الرَّجُلُ يَسْهُو فِي صَلَاتِهِ فَلَا يَدْرِي كَمْ صَلَّى قَالَ عَبْدُ الرَّحْمَنِ سَمِعْتُ رَسُولَ اللهِ ﷺ يَقُولُ إِذَا سَهَا الرَّجُلُ فَلَمْ يَدْرِ اثْنَتَيْنِ أَوْ ثَلَاثًا أَوْ أَرْبَعًا فَلْيَجْعَلِ السَّهْوَ فِي الزِّيَادَةِ وَلْيَسْجُدْ سَجْدَتَيْنِ قَالَ مُحَمَّدُ بْنُ إِسْحَاقَ فَلَقِيتُ حُسَيْنَ بْنَ عَبْدِ اللهِ فَذَاكَرْتُهُ فِي هَذَا الْحَدِيثِ فَقَالَ لِي هَلْ أَسْنَدَهُ؟ قُلْتُ لَا قَالَ لَكِنْ حَدَّثَنِي مَكْحُولٌ عَنْ كُرَيْبٍ عَنِ ابْنِ عَبَّاسٍ عَنْ عَبْدِ الرَّحْمَنِ بْنِ عَوْفٍ عَنِ النَّبِيِّ ﷺ بِمِثْلِهِ بِهَذَا الْحَدِيثِ وَرَوَاهُ الْمُحَارِبِيُّ عَنْ مُحَمَّدِ بْنِ إِسْحَاقَ بِمَعْنَى رِوَايَةِ ابْنِ عُلَيَّةَ فَصَارَ وَصْلُ الْحَدِيثِ لِحُسَيْنِ بْنِ عَبْدِ اللهِ وَهُوَ ضَعِيفٌ إِلَّا أَنَّ لَهُ شَاهِدًا مِنْ حَدِيثِ مَكْحُولٍ 3806 أَخْبَرَنَا أَبُو بَكْرِ بْنُ الْحَارِثِ الْفَقِيهُ أنبأ أَبُو مُحَمَّدٍ عَبْدُ اللهِ بْنُ مُحَمَّدِ بْنِ جَعْفَرٍ الْمَعْرُوفُ بِأَبِي الشَّيْخِ الْأَصْبَهَانِيِّ ثنا أَحْمَدُ بْنُ عَمْرٍو يَعْنِي ابْنَ أَبِي عَاصِمٍ ثنا سُلَيْمَانُ بْنُ يُوسُفَ ثنا عَبْدُ اللهِ بْنُ وَاقِدٍ الْحَرَّانِيُّ ثنا عَبْدُ الرَّحْمَنِ بْنُ ثَابِتِ بْنِ ثَوْبَانَ عَنْ أَبِيهِ عَنْ مَكْحُولٍ فَذَكَرَهُ نَحْوَ رِوَايَةِ ابْنِ إِسْحَاقَ عَنْ مَكْحُولٍ عَنْ كُرَيْبٍ عَنْ ابْنِ عَبَّاسٍ عَنْ عَبْدِ الرَّحْمَنِ بْنِ عَوْفٍ عَنِ النَّبِيِّ ﷺ وَرُوِيَ أَيْضًا عَنْ ثَوْرِ بْنِ يَزِيدَ عَنْ مَكْحُولٍ كَذَلِكَ مَوْصُولًا وَرُوِي مِنْ وَجْهٍ آخَرَ عَنِ ابْنِ عَبَّاسٍ  

[Machine] Should I not tell you a story that I heard from the Messenger of Allah ﷺ? We said, "Yes." He said, "I bear witness that there is no god but Allah, and I heard the Messenger of Allah ﷺ say, 'If one of you has doubt in the deficiency of his prayer, then let him continue to pray until he reaches doubt in the abundance of it, and likewise.'"  

أَلَا أُحَدِّثُكُمْ حَدِيثًا سَمِعْتُهُ مِنْ رَسُولِ اللهِ ﷺ؟ قُلْنَا بَلَى قَالَ أَشْهَدُ شَهَادَةَ اللهِ لَسَمِعْتُ رَسُولَ اللهِ ﷺ يَقُولُ إِذَا كَانَ أَحَدُكُمْ فِي شَكٍّ مِنَ النُّقْصَانِ فِي صَلَاتِهِ فَلْيُصَلِّ حَتَّى يَكُونَ فِي شَكٍّ مِنَ الزِّيَادَةِ وَكَذَلِكَ  

[Machine] Abu Abdullah Al-Hafiz in Al-Fawaid Al-Kabir informed us that Abu Al-Abbas reported to us, who reported to us that Ahmad bin Hazim bin Abu Gharzah narrated from Ja'far, who narrated from Sa'id, meaning the son of Abu Aroobah, from Qatadah, from Anas, from the Prophet ﷺ, who said: "If one of you has doubts in his prayer and he does not know whether he prayed two or three rak'ahs, then he should leave the doubt and act upon certainty." Ja'far said, "This is the opinion of Ibn 'Awf, and likewise it is in the original narration." And Allah knows best.  

أَخْبَرَنَا أَبُو عَبْدِ اللهِ الْحَافِظُ فِي الْفَوَائِدِ الْكَبِيرِ لِأَبِي الْعَبَّاسِ ثنا أَبُو الْعَبَّاسِ مُحَمَّدُ بْنُ يَعْقُوبَ ثنا أَحْمَدُ بْنُ حَازِمِ بْنِ أَبِي غَرَزَةَ أنبأ جَعْفَرٌ أنبأ سَعِيدٌ يَعْنِي ابْنَ أَبِي عَرُوبَةَ عَنْ قَتَادَةَ عَنْ أَنَسٍ عَنِ النَّبِيِّ ﷺ قَالَ إِذَا شَكَّ أَحَدُكُمْ فِي صَلَاتِهِ فَلَمْ يَدْرِ اثْنَتَيْنِ صَلَّى أَوْ ثَلَاثًا فَلْيُلْقِ الشَّكَّ وَلْيَبْنِ عَلَى الْيَقِينِ جَعْفَرٌ هَذَا هُوَ ابْنُ عَوْفٍ وَكَذَا كَانَ فِي الْأَصْلِ سَعِيدٌ يَعْنِي ابْنَ أَبِي عَرُوبَةَ وَاللهُ أَعْلَمُ  

[Machine] The Messenger of Allah ﷺ said, "When one of you prays, he does not know whether he has prayed three or four rak'ahs, so let him prostrate a rak'ah, performing its bowing and prostration well, and then let him perform two prostrations. Its narrators are trustworthy, and Malik ibn Anas has confirmed it in Al-Muwatta."  

قَالَ رَسُولُ اللهِ ﷺ إِذَا صَلَّى أَحَدُكُمْ فَلَا يَدْرِي كَمْ صَلَّى ثَلَاثًا أَمْ أَرْبَعًا فَلْيَرْكَعْ رَكْعَةً يُحْسِنُ رُكُوعَهَا وَسُجُودَهَا ثُمَّ يَسْجُدُ سَجْدَتَيْنِ رُوَاتُهُ ثِقَاتٌ وَقَدْ وَقَفَهُ مَالِكُ بْنُ أَنَسٍ فِي الْمُوَطَّأِ  

[Machine] If one forgets a prayer, they should perform it as soon as they remember, then make two prostrations while sitting.  

أَنَّهُ نَسِيَ مِنْ صَلَاتِهِ فَلْيُصَلِّهِ ثُمَّ يَسْجُدُ سَجْدَتَيْنِ وَهُوَ جَالِسٌ  

[Machine] If one forgets a prayer, they should make it up.  

أَنَّهُ نَسِيَ مِنْ صَلَاتِهِ فَلْيُصَلِّهِ  

[Machine] About the one who doubts his prayer, he does not know whether he prayed three or four rak'ahs, both of them said: "Let him stand and pray another rak'ah and then perform two prostrations if he prayed."  

عَنِ الَّذِي يَشُكُّ فِي صَلَاتِهِ فَلَا يَدْرِي أَثْلَاثًا صَلَّى أَمْ أَرْبَعًا فَكِلَاهُمَا قَالَا فَلْيَقُمْ فَلْيُصَلِّ رَكْعَةً أُخْرَى وَلْيَسْجُدْ سَجْدَتَيْنِ إِذَا صَلَّى