Abu Hurairah (May Allah be pleased with him) reported:
The Prophet ﷺ said, "Whosoever performs Qiyam during Lailat-ul-Qadr (Night of Decree), with Faith and being hopeful of Allah's reward, will have his former sins forgiven."

[Al-Bukhari and Muslim].

وعن أبي هريرة رضي الله عنه، عن النبي ﷺ قال: "من قام ليلة القدر إيمانا واحتسابًا غفر له ما تقدم من ذنبه". ((متفق عليه)) .