Language:
كتاب السهو
22  
Forgetfulness in Prayer
(5)
Chapter: To say Takbir in the prostrations of Sahw
(5)
باب مَنْ يُكَبِّرُ فِي سَجْدَتَىِ السَّهْوِ
Sahih al-Bukhari 1229

Narrated Abu Huraira:

The Prophet (ﷺ) offered one of the evening prayers (the sub-narrator Muhammad said, "I think that it was most probably the `Asr prayer") and he finished it after offering two rak`at only. He then stood near a price of wood in front of the Mosque and put his hand over it. Abu Bakr and `Umar 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 rak`at 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.

حَدَّثَنَا حَفْصُ بْنُ عُمَرَ، حَدَّثَنَا يَزِيدُ بْنُ إِبْرَاهِيمَ، عَنْ مُحَمَّدٍ، عَنْ أَبِي هُرَيْرَةَ ـ رضى الله عنه ـ قَالَ صَلَّى النَّبِيُّ صلى الله عليه وسلم إِحْدَى صَلاَتَىِ الْعَشِيِّ ـ قَالَ مُحَمَّدٌ وَأَكْثَرُ ظَنِّي الْعَصْرَ ـ رَكْعَتَيْنِ ثُمَّ سَلَّمَ ثُمَّ قَامَ إِلَى خَشَبَةٍ فِي مُقَدَّمِ الْمَسْجِدِ فَوَضَعَ يَدَهُ عَلَيْهَا وَفِيهِمْ أَبُو بَكْرٍ وَعُمَرُ ـ رضى الله عنهما ـ فَهَابَا أَنْ يُكَلِّمَاهُ وَخَرَجَ سَرَعَانُ النَّاسِ فَقَالُوا أَقَصُرَتِ الصَّلاَةُ وَرَجُلٌ يَدْعُوهُ النَّبِيُّ صلى الله عليه وسلم 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.‏
Reference : Sahih al-Bukhari 1229
In-book reference : Book 22, Hadith 7
USC-MSA web (English) reference : Vol. 2, Book 22, Hadith 321
  (deprecated numbering scheme)