وَعَن معَاذَة قَالَتْ: سَأَلْتُ عَائِشَةَ: كَمْ كَانَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ يُصَلِّي صَلَاةَ الضُّحَى؟ قَالَتْ: أَرْبَعَ رَكَعَاتٍ وَيَزِيدُ مَا شَاءَ اللَّهُ. رَوَاهُ مُسلم
Mu'adha said she asked ‘A’isha how many rak'as God’s Messenger prayed at the forenoon prayer, and she replied, “Four rak'as , but sometimes more, as God pleased.” Muslim transmitted it.