Riyad as-Salihin, Book 9, Hadith 1189 (In-Book)

Abu Hurairah (May Allah be pleased with him) reported: The Prophet 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 صلى الله عليه وسلم قال‏:‏ ‏ "‏من قام ليلة القدر إيمانا واحتسابًا غفر له ما تقدم من ذنبه‏" ‏‏.‏ ‏(‏‏(‏متفق عليه‏)‏‏)‏ ‏.‏

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