ذِكْرُ الْبَيَانِ بِأَنَّ الْمُتَحَرِّيَ فِي الصَّلَاةِ عِنْدَ شَكِّهِ عَلَيْهِ أَنْ يَسْجُدَ سَجْدَتَيِ السَّهْوِ بَعْدَ السَّلَامِ
The Prophet ﷺ prayed (and the sub-narrator Ibrahim said, "I do not know whether he prayed more or less than usual"), and when he had finished the prayers he was asked, "O Messenger of Allah ﷺ! Has there been any change in the prayers?" He said, "What is it?' The people said, "You have prayed so much and so much." So the Prophet ﷺ bent his legs, faced the Qibla and performed two prostration's (of Sahu) and finished his prayers with Taslim (by turning his face to right and left saying: 'As-Salamu ʿAlaikum- Warahmat-ullah'). When he turned his face to us he said, "If there had been anything changed in the prayer, surely I would have informed you but I am a human being like you and liable to forget like you. So if I forget remind me and if anyone of you is doubtful about his prayer, he should follow what he thinks to be correct and complete his prayer accordingly and finish it and do two prostrations (of Sahu). (Using translation from Bukhārī 401)
عَبْدُ اللَّهِ صَلَّى رَسُولُ اللَّهِ ﷺ صَلَاةً قَالَ إِبْرَاهِيمُ لَا أَدْرِي أَزَادَ نَقَصَ فَلَمَّا سَلَّمَ قِيلَ لَهُ يَا رَسُولَ اللَّهِ أَحَدَثَ فِي الصَّلَاةِ شَيْءٌ؟ قَالَ «لَا وَمَا ذَاكَ؟ » قَالُوا صَلَّيْتَ كَذَا وَكَذَا قَالَ فَثَنَى رِجْلَهُ وَاسْتَقْبَلَ الْقِبْلَةَ وَسَجَدَ سَجْدَتَيْنِ ثُمَّ سَلَّمَ فَلَمَّا أَقْبَلَ عَلَيْنَا بِوَجْهِهِ قَالَ «إِنَّهُ لَوْ حَدَثَ فِي الصَّلَاةِ شَيْءٌ أَنْبَأْتُكُمْ بِهِ وَلَكِنِّي إِنَّمَا أَنَا بَشَرٌ مِثْلُكُمْ أَنْسَى كَمَا تَنْسَوْنَ فَإِذَا نَسِيتُ فَذَكِّرُونِي وَإِذَا شَكَّ أَحَدُكُمْ فِي صَلَاتِهِ فَلْيَتَحَرَّ الصَّوَابَ وَلْيُتِمَّ عَلَيْهِ ثُمَّ لْيُسَلِّمْ ثُمَّ لْيَسْجُدْ سَجْدَتَيْنِ»