(28) Chapter. To observe Saum [(fasts) (according to Islamic teachings)] during the month of Ramadan (sincerely and faithfully) hoping for Allah’s Rewards only, is a part of faith.
Narrated Abu Huraira: Allah's Apostle said, "Whoever observes fasts during the month of Ramadan out of sincere faith, and hoping to attain Allah's rewards, then all his past sins will be forgiven."
Hadith ReferenceSahih Bukhari / The Book of Belief (Faith) / Hadith: 38
Hadith Gradingمحدثین:أحاديث صحيح البخاريّ كلّها صحيحة