حَدَّثَنَا عَلِيُّ بْنُ مُحَمَّدٍ، وَأَبُو كُرَيْبٍ وَأَحْمَدُ بْنُ سِنَانٍ قَالُوا حَدَّثَنَا أَبُو أُسَامَةَ، عَنْ عُبَيْدِ اللَّهِ بْنِ عُمَرَ، عَنْ نَافِعٍ، عَنِ ابْنِ عُمَرَ، أَنَّ رَسُولَ اللَّهِ ـ صلى الله عليه وسلم ـ سَهَا فَسَلَّمَ فِي الرَّكْعَتَيْنِ ‏.‏ فَقَالَ لَهُ رَجُلٌ يُقَالُ لَهُ ذُو الْيَدَيْنِ يَا رَسُولَ اللَّهِ أَقَصُرَتِ الصَّلاَةُ أَمْ نَسِيتَ قَالَ ‏"‏ مَا قَصُرَتْ وَمَا نَسِيتُ ‏"‏ ‏.‏ قَالَ إِنَّكَ صَلَّيْتَ رَكْعَتَيْنِ ‏.‏ قَالَ ‏"‏ أَكَمَا يَقُولُ ذُو الْيَدَيْنِ ‏"‏ ‏.‏ قَالُوا نَعَمْ ‏.‏ فَتَقَدَّمَ فَصَلَّى رَكْعَتَيْنِ ثُمَّ سَلَّمَ ثُمَّ سَجَدَ سَجْدَتَىِ السَّهْوِ ‏.‏

It wasnarrated from Ibn ‘Umar that the Messenger of Allah (PBUH)forgotand said the Taslim after two Rak’ah. A man who was calledDhul-Yadain said to him: ‘O Messenger of Allah, has the prayer beenshortened or did you forget?’ He said: ‘It has not been shortenedandI did not forget.’ He said: ‘But you prayed two Rak’ah.’ Hesaid: ‘Is whatDhul-Yadain says true?’ They said: ‘Yes.’ Sohe went forward andperformed two Rak’ah and said the Salam, thenhe prostrated twice forprostrations of forgetfulness. Translation Not Available

Book Ref: Sunan Ibn Majah Book 5 Hadith 1213
Web Ref:  Sunan Ibn Majah Vol 1 Book 5 Hadith 1213