The Messenger of Allah ﷺ offered one of the afternoon prayers with five (rak'ahs), and it was said to him: "Has something been added to the prayer?" He said: 'Why are you asking?' They said: 'You prayed five.' He said: 'I am only human, I forget as you forget, and I remember as you remember.' Then he prostrated twice then ended his prayer. (Using translation from Nasāʾī 1259)
أَنَّ رَسُولَ اللهِ ﷺ صَلَّى إِحْدَى صَلَاتِي الْعَشِيِّ خَمْسًا فَقِيلَ لَهُ أَزِيدَ فِي الصَّلَاةِ؟ فَقَالَ «وَمَا ذَاكَ؟» قَالُوا صَلَّيْتَ خَمْسًا قَالَ «إِنَّمَا أَنَا بَشَرٌ أَنْسَى كَمَا تَنْسَوْنَ وَأَذْكُرُ كَمَا تَذْكُرُونَ» فَسَجَدَ سَجْدَتَيْنِ ثُمَّ انْفَتَلَ