Riyad as-Salihin, Book 20, Hadith 1877 (In-Book) ⓘ
'Aishah (May Allah be pleased with her) reported: Prior to his demise, the Messenger of Allah used to supplicate frequently: Subhan Allahi wa bihamdihi; Astaghfirullaha wa atubu ilaihi (Allah is free from imperfection, and I begin with praising Him. I beg forgiveness from Allah and I turn to Him in repentance."[Al-Bukhari and Muslim].
وعن عائشة رضي الله عنها قالت: كان رسول الله صلى الله عليه وسلم يكثر أن يقول قبل موته "سبحان الله وبحمده، أستغفر الله، وأتوب إليه" ((متفق عليه)).