Sayyiduna Abu Hurairah, may Allah be pleased with him, narrates this statement of the Prophet Muhammad, peace and blessings be upon him: "Whoever, with faith and seeking reward, performs voluntary prayers and fasts during Ramadan, his past sins are forgiven; and whoever, with faith and seeking reward, performs voluntary prayers during the Night of Qadr, his past sins are forgiven."
Hadith Referenceصحیح ابن حبان / كتاب الصوم / 3682
Hadith Gradingفضيلة الشيخ الإمام محمد ناصر الدين الألبانيحسن صحيح - «صحيح أبي داود» (1241): ق.فضيلة الشيخ العلّامة شُعيب الأرناؤوطالحديث صحيح