that he asked 'A'isha ؓ how many rak'ahs Messenger of Allah ﷺ prayed at the forenoon prayer. She replied: Four rak'ahs, but sometimes more as he pleased.
أَنَّهَا سَأَلَتْ عَائِشَةَ ؓ كَمْ كَانَ رَسُولُ اللَّهِ ﷺ يُصَلِّي صَلاَةَ الضُّحَى قَالَتْ أَرْبَعَ رَكَعَاتٍ وَيَزِيدُ مَا شَاءَ