The Messenger of Allah ﷺ said prayer and he omitted or committed (something). Ibrahim (one of the narrators of this hadith) said: It is my doubt, and it was said: Messenger of Allah, has there been any addition to the prayer? He (the Holy Prophet) said: Verily I am a human being like you. I forget just as you forget so when any one of you forgets, he must perform two prostrations, and he (the Holy Prophet) was sitting and then the Messenger of Allah ﷺ turned (his face towards the Qibla) and performed two prostrations.  

صَلَّى رَسُولُ اللَّهِ ﷺ فَزَادَ أَوْ نَقَصَ قَالَ إِبْرَاهِيمُ وَالْوَهْمُ مِنِّي فَقِيلَ يَا رَسُولَ اللَّهِ أَزِيدَ فِي الصَّلاَةِ شَىْءٌ فَقَالَ إِنَّمَا أَنَا بَشَرٌ مِثْلُكُمْ أَنْسَى كَمَا تَنْسَوْنَ فَإِذَا نَسِيَ أَحَدُكُمْ فَلْيَسْجُدْ سَجْدَتَيْنِ وَهُوَ جَالِسٌ ثُمَّ تَحَوَّلَ رَسُولُ اللَّهِ ﷺ فَسَجَدَ سَجْدَتَيْنِ  

[Machine] The Messenger of Allahﷺ prayed with us, and sometimes he added and sometimes he omitted. Ibrahim said, "The forgetfulness was a result of my doing." So we asked him, "O Messenger of Allah, did you introduce something new in the prayer?" He said, "What is that?" We said, "You prayed before in such and such a way." He said, "Indeed, I am only a human, I forget just as you forget. So if any one of you forgets something, let him prostrate twice, then turn and prostrate twice."  

صَلَّى بِنَا رَسُولُ اللهِ ﷺ فَإِمَّا زَادَ وَإِمَّا نَقَصَ قَالَ إِبْرَاهِيمُ وَإِنِمَّا جَاءَ نِسْيَانُ ذَلِكَ مِنْ قِبَلِي فَقُلْنَا يَا رَسُولَ اللهِ أَحَدَثَ فِي الصَّلَاةِ شَيْءٌ؟ قَالَ وَمَا ذَاكَ؟ قُلْنَا صَلَّيْتَ قَبْلُ كَذَا وَكَذَا قَالَ إِنَّمَا أَنَا بَشَرٌ أَنْسَى كَمَا تَنْسَوْنَ فَإِذَا نَسِيَ أَحَدُكُمْ فَلْيَسْجُدْ سَجْدَتَيْنِ ثُمَّ تَحَوَّلَ فَسَجَدَ سَجْدَتَيْنِ