Sahih al-Bukhari, Hadith 714 ⓘ

Narrated Abu Huraira: Once Allah's Messenger prayed two rak`at (instead of four) and finished his prayer. Dhul-Yadain asked him whether the prayer had been reduced or whether he had forgotten. Allah's Messenger asked the people whether Dhul-Yadain was telling the truth. The people replied in the affirmative. Then Allah's Apostle stood up, offered the remaining two rak`at and then finished his prayer with Taslim and then said, "Allahu Akbar." He followed it with two prostrations like ordinary prostrations or a bit longer.

حَدَّثَنَا عَبْدُ اللَّهِ بْنُ مَسْلَمَةَ، عَنْ مَالِكِ بْنِ أَنَسٍ، عَنْ أَيُّوبَ بْنِ أَبِي تَمِيمَةَ السَّخْتِيَانِيِّ، عَنْ مُحَمَّدِ بْنِ سِيرِينَ، عَنْ أَبِي هُرَيْرَةَ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم انْصَرَفَ مِنَ اثْنَتَيْنِ، فَقَالَ لَهُ ذُو الْيَدَيْنِ أَقَصُرَتِ الصَّلاَةُ أَمْ نَسِيتَ يَا رَسُولَ اللَّهِ فَقَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم ‏ "‏ أَصَدَقَ ذُو الْيَدَيْنِ ‏" ‏‏.‏ فَقَالَ النَّاسُ نَعَمْ‏.‏ فَقَامَ رَسُولُ اللَّهِ صلى الله عليه وسلم فَصَلَّى اثْنَتَيْنِ أُخْرَيَيْنِ ثُمَّ سَلَّمَ، ثُمَّ كَبَّرَ فَسَجَدَ مِثْلَ سُجُودِهِ أَوْ أَطْوَلَ‏.‏