Abu Hurairah (May Allah be pleased with him) reported:
The Messenger of Allah ﷺ said, "He who observes optional prayer (Tarawih prayers) throughout Ramadan, out of sincerity of Faith and in the hope of earning reward will have his past sins pardoned."

[Al-Bukhari and Muslim].

عن أبي هريرة رضي الله عنه، أن رسول الله ﷺ قال: "من قام رمضان إيمانًا واحتسابًا غفر له ما تقدم من ذنبه". ((متفق عليه)) .