Riyad as-Salihin, Book 9, Hadith 1141 (In-Book) ⓘ
'Aishah (May Allah be pleased with her) reported: The Messenger of Allah used to perform four Rak'ah of Duha prayer (at the forenoon) and would add to them whatever Allah wished.[Muslim].
وعن عائشة رضي الله عنها قالت: كان رسول الله صلى الله عليه وسلم يصلي الضحى أربعًا ويزيد ما شاء الله . ((رواه مسلم)).