The Prophet ﷺ offered one of the evening prayers (the sub-narrator Muhammad said, "I think that it was most probably the ʿAsr prayer") and he finished it after offering two rakʿat only. He then stood near a price of wood in front of the Mosque and put his hand over it. Abu Bakr and ʿUmar were amongst those who were present, but they dared not talk to him about that (because of excessive respect for him), and those who were in a hurry went out. They said, "Has the prayer been reduced?" A man who was called Dhul-Yadain by the Prophet ﷺ said (to the Prophet), "Has the prayer been reduced or have you forgotten?" He said, "Neither have I forgotten, nor has the prayer been reduced." He said, "Certainly you have forgotten." So the Prophet ﷺ offered two more rakʿat and performed Taslim and then said Takbir and performed a prostration of Sahu like his ordinary prostration or a bit longer and then raised his head and said Takbir and then put his head down and performed a prostration like his ordinary prostration or a bit longer, and then raised his head and said Takbir.  

صَلَّى النَّبِيُّ ﷺ إِحْدَى صَلاَتَىِ الْعَشِيِّ قَالَ مُحَمَّدٌ وَأَكْثَرُ ظَنِّي الْعَصْرَ رَكْعَتَيْنِ ثُمَّ سَلَّمَ ثُمَّ قَامَ إِلَى خَشَبَةٍ فِي مُقَدَّمِ الْمَسْجِدِ فَوَضَعَ يَدَهُ عَلَيْهَا وَفِيهِمْ أَبُو بَكْرٍ وَعُمَرُ ؓ فَهَابَا أَنْ يُكَلِّمَاهُ وَخَرَجَ سَرَعَانُ النَّاسِ فَقَالُوا أَقَصُرَتِ الصَّلاَةُ وَرَجُلٌ يَدْعُوهُ النَّبِيُّ ﷺ ذُو الْيَدَيْنِ فَقَالَ أَنَسِيتَ أَمْ قَصُرَتْ فَقَالَ لَمْ أَنْسَ وَلَمْ تُقْصَرْ قَالَ بَلَى قَدْ نَسِيتَ فَصَلَّى رَكْعَتَيْنِ ثُمَّ سَلَّمَ ثُمَّ كَبَّرَ فَسَجَدَ مِثْلَ سُجُودِهِ أَوْ أَطْوَلَ ثُمَّ رَفَعَ رَأْسَهُ فَكَبَّرَ ثُمَّ وَضَعَ رَأْسَهُ فَكَبَّرَ فَسَجَدَ مِثْلَ سُجُودِهِ أَوْ أَطْوَلَ ثُمَّ رَفَعَ رَأْسَهُ وَكَبَّرَ  

(the ally of Bani ʿAbdul Muttalib) Messenger of Allah ﷺ stood up for the Zuhr prayer and he should have sat (after the second rakʿa but he stood up for the third rakʿa without sitting for Tashah-hud) and when he finished the prayer he performed two prostrations and said Takbir on each prostration while sitting, before ending (the prayer) with Taslim; and the people too performed the two prostrations with him instead of the sitting he forgot.  

أَنَّ رَسُولَ اللَّهِ ﷺ قَامَ فِي صَلاَةِ الظُّهْرِ وَعَلَيْهِ جُلُوسٌ فَلَمَّا أَتَمَّ صَلاَتَهُ سَجَدَ سَجْدَتَيْنِ فَكَبَّرَ فِي كُلِّ سَجْدَةٍ وَهُوَ جَالِسٌ قَبْلَ أَنْ يُسَلِّمَ وَسَجَدَهُمَا النَّاسُ مَعَهُ مَكَانَ مَا نَسِيَ مِنَ الْجُلُوسِ