Abu Sa’id al-Khudri reported: The Messenger of Allah, peace and blessings be upon him, said, “If one of you doubts his prayer and does not know how much he has prayed, whether three or four cycles, then let him put aside his doubt and act upon what he is certain of. Then, perform two prostrations before he offers salutations of peace. If he had mistakenly prayed five cycles, the prostrations would make his prayer even. If he had prayed precisely four cycles, it would be humiliation for Satan.”
Source: Ṣaḥīḥ Muslim 571
Grade: Sahih (authentic) according to Muslim
Imam al-Nawawi commented, “Malik, Al-Shafi’i, and Ahmad, may Allah be pleased with them, as well as the majority, said that when one doubts his prayer, whether he prayed three or four cycles, one is required to act based upon what is known for sure. Then, one completes the fourth cycle and performs the prostrations of forgetfulness.”
Source: Sharḥ al-Nawawī ‘alá Ṣaḥīḥ Muslim 5/58
عَنْ أَبِي سَعِيدٍ الْخُدْرِيِّ قَالَ قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ إِذَا شَكَّ أَحَدُكُمْ فِي صَلَاتِهِ فَلَمْ يَدْرِ كَمْ صَلَّى ثَلَاثًا أَمْ أَرْبَعًا فَلْيَطْرَحْ الشَّكَّ وَلْيَبْنِ عَلَى مَا اسْتَيْقَنَ ثُمَّ يَسْجُدُ سَجْدَتَيْنِ قَبْلَ أَنْ يُسَلِّمَ فَإِنْ كَانَ صَلَّى خَمْسًا شَفَعْنَ لَهُ صَلَاتَهُ وَإِنْ كَانَ صَلَّى إِتْمَامًا لِأَرْبَعٍ كَانَتَا تَرْغِيمًا لِلشَّيْطَانِ
571 صحيح مسلم كتاب المساجد ومواضع الصلاة باب السهو في الصلاة والسجود له
قال النووي وَقَالَ مَالِكٌ وَالشَّافِعِيُّ وَأَحْمَدُ رَضِيَ اللَّهُ عَنْهُمْ وَالْجُمْهُورُ مَتَى شَكَّ فِي صَلَاتِهِ هَلْ صَلَّى ثَلَاثًا أَمْ أَرْبَعًا مَثَلًا لَزِمَهُ الْبِنَاءُ عَلَى الْيَقِينِ فَيَجِبُ أَنْ يَأْتِيَ بِرَابِعَةٍ وَيَسْجُدَ لِلسَّهْوِ
5/58 شرح النووي على مسلم كتاب المساجد باب السهو في الصلاة والسجود له
