“I heard the Messenger of Allah ﷺ say: ‘If anyone of you is uncertain as to whether he has prayed one or two Rak’ah, let him assume it is one. If he is uncertain as to whether he has prayed two or three, let him assume it is two. If he is uncertain as to whether he has prayed three or four, let him assume it is three. Then let him complete what is left of his prayer, so that the doubt will be about what is more. Then let him prostrate twice while he is sitting, before the Taslim (saying the Salam).’”  

سَمِعْتُ رَسُولَ اللَّهِ ﷺ يَقُولُ إِذَا شَكَّ أَحَدُكُمْ فِي الثِّنْتَيْنِ وَالْوَاحِدَةِ فَلْيَجْعَلْهَا وَاحِدَةً وَإِذَا شَكَّ فِي الثِّنْتَيْنِ وَالثَّلاَثِ فَلْيَجْعَلْهَا ثِنْتَيْنِ وَإِذَا شَكَّ فِي الثَّلاَثِ وَالأَرْبَعِ فَلْيَجْعَلْهَا ثَلاَثًا ثُمَّ لْيُتِمَّ مَا بَقِيَ مِنْ صَلاَتِهِ حَتَّى يَكُونَ الْوَهْمُ فِي الزِّيَادَةِ ثُمَّ يَسْجُدْ سَجْدَتَيْنِ وَهُوَ جَالِسٌ قَبْلَ أَنْ يُسَلِّمَ  

[Machine] I heard from the Messenger of Allah or one of his companions, "When a man is uncertain about his prayer, what should he do?" He said, "While in this state, Abdullah ibn Awf approached and asked, 'Who are you two?'" Umar said, "I asked this young man if he had heard from the Messenger of Allah or any of his companions, what should one do when uncertain about their prayer?" Abdullah ibn Awf said, "I heard the Messenger of Allah say, 'If one of you is uncertain about their prayer and does not know whether they have prayed one or two (units), then let them make it one. And if they do not know whether they have prayed two or three, then let them make it two. And if they do not know whether they have prayed three or four, then let them make it three. Then let them prostrate when they finish their prayer while seated before they give the salutations with two prostrations.'"  

سَمِعْتَ مِنْ رَسُولِ اللهِ ﷺ أَوْ مِنْ أَحَدٍ مِنْ أَصْحَابِهِ إِذَا شَكَّ الرَّجُلُ فِي صَلاتِهِ مَاذَا يَصْنَعُ؟ قَالَ فَبَيْنَا هُوَ كَذَلِكَ إِذِ اقْبَلَ عَبْدُ الرَّحْمَنِ بْنُ عَوْفٍ فَقَالَ فِيمَ أَنْتُمَا؟فَقَالَ عُمَرُ سَأَلْتُ هَذَا الْغُلامَ هَلْ سَمِعَ مِنْ رَسُولِ اللهِ ﷺ أَوْ أَحَدٍ مِنْ أَصْحَابِهِ إِذَا شَكَّ الرَّجُلُ فِي صَلاتِهِ مَاذَا يَصْنَعُ؟ فَقَالَ عَبْدُ الرَّحْمَنِ سَمِعْتُ رَسُولَ اللهِ ﷺ يَقُولُ إِذَا شَكَّ أَحَدُكُمْ فِي صَلاتِهِ فَلَمْ يَدْرِ أَوَاحِدَةً صَلَّى أَمْ ثِنْتَيْنِ؟ فَلْيَجْعَلْهَا وَاحِدَةً وَإِذَا لَمْ يَدْرِ ثِنْتَيْنِ صَلَّى أَمْ ثَلاثًا؟ فَلْيَجْعَلْهَا ثِنْتَيْنِ وَإِذَا لَمْ يَدْرِ أَثَلاثًا صَلَّى أَمِ ارْبَعًا؟ فَلْيَجْعَلْهَا ثَلاثًا ثُمَّ يَسْجُدِ اذَا فَرَغَ مِنْ صَلاتِهِ وَهُوَ جَالِسٌ قَبْلَ أَنْ يُسَلِّمَ سَجْدَتَيْنِ  

[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  

“I heard the Messenger of Allah ﷺ say: ‘If anyone of you is uncertain as to whether he has prayed one or two Rak’ah, let him assume it is one. If he is uncertain as to whether he has prayed two or three, let him assume it is two. If he is uncertain as to whether he has prayed three or four, let him assume it is three. Then let him complete what is left of his prayer, so that the doubt will be about what is more. Then let him prostrate twice while he is sitting, before the Taslim (saying the Salam).’” (Using translation from Ibn Mājah 1209)   

"إذَا شكَّ أَحدُكمْ في الاثْنتينِ أو الواحِدَةِ فَليجعلْها واحدةً وإذا شَكَّ في الثنْتَين والثَّلاثِ فليَجْعَلها اثنتين، وإذا شَكَّ في الثلاث والأرْبَعِ فليجعلها ثلاثًا، حتَّى يكونَ الوهْمُ في الزيادة، ثم لْيُتِمَّ ما بَقِي من صلاته، ثم يسْجُد سجدتين وهو جالسٌ قْبلَ أنْ يسلِّمَ ".  

"إِذا شَكَّ أحدُكُمْ في صَلاتِه فلم يَدْر زادَ أوْ نَقَص؟ فإِنْ كانَ شكّ في الواحدةِ وَالثِّنتين فليجْعلها واحدةً حتَّى يكونَ الوهْمُ في الزِّيادةِ ثمَّ يَسْجُدْ سجدتينِ وهو جالسٌ قَبْل أنْ يُسَلِّمَ ثُمَّ يُسَلِّمْ ".