عَنْ عَبْدِ اللَّهِ، قَالَ صَلَّى بِنَا النَّبِيُّ صلى الله عليه وسلم الظُّهْرَ خَمْسًا فَقِيلَ أَزِيدَ فِي الصَّلاَةِ قَالَ: وَمَا ذَاكَ. قَالُوا صَلَّيْتَ خَمْسًا. فَسَجَدَ سَجْدَتَيْنِ بَعْدَ مَا سَلَّمَ.
Hazrat Abdullah ibn Mas‘udra reports, “The Holy Prophetsa once led us in Zuhr and performed five rak‘at. Someone asked, ‘Has the prayer been increased?’ He replied, ‘What do you mean?’ They said, ‘You offered five rak‘at.’ So, after concluding the prayer with salam, he performed two prostrations of forgetfulness [sujud as-sahw].
(Sahih al-Bukhari, Kitab akhbari l-ahad, Bab ma ja’a fi ijazati khabari l-wahidi s-saduqi fi l-adhani wa s-salati wa s-sawmi wa l-fara’idi wa l-ahkam, Hadith 7249)