Narrated 'Abdullah:

"Once the Prophet offered five Rakat in Zuhr prayer. He was asked, "Is there an increase in the prayer?" The Prophet ﷺ said, "And what is it?" They said, "You have prayed five Rakat.' So he bent his legs and performed two prostrations (of Sahu).

حَدَّثَنَا مُسَدَّدٌ، قَالَ حَدَّثَنَا يَحْيَى، عَنْ شُعْبَةَ، عَنِ الْحَكَمِ، عَنْ إِبْرَاهِيمَ، عَنْ عَلْقَمَةَ، عَنْ عَبْدِ اللَّهِ، قَالَ صَلَّى النَّبِيُّ ﷺ الظُّهْرَ خَمْسًا فَقَالُوا أَزِيدَ فِي الصَّلاَةِ قَالَ
" وَمَا ذَاكَ ". قَالُوا صَلَّيْتَ خَمْسًا. فَثَنَى رِجْلَيْهِ وَسَجَدَ سَجْدَتَيْنِ.