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.
أَنَّ رَسُولَ اللَّهِ ﷺ صَلَّى إِحْدَى صَلاَتَىِ الْعَشِيِّ خَمْسًا فَقِيلَ لَهُ أَزِيدَ فِي الصَّلاَةِ فَقَالَ وَمَا ذَاكَ قَالُوا صَلَّيْتَ خَمْسًا قَالَ إِنَّمَا أَنَا بَشَرٌ أَنْسَى كَمَا تَنْسَوْنَ وَأَذْكُرُ كَمَا تَذْكُرُونَ فَسَجَدَ سَجْدَتَيْنِ ثُمَّ انْفَتَلَ