صَحِيحُ الْبُخَارِيِّ
Sahih al-Bukhari 38
Belief
To observe fasting (according to Islamic teachings)] during the month of Ramadan (sincerely and faithfully) hoping for Allah's Reward only, is a part of faith
حَدَّثَنَا ابْنُ سَلاَمٍ، قَالَ أَخْبَرَنَا مُحَمَّدُ بْنُ فُضَيْلٍ، قَالَ حَدَّثَنَا يَحْيَى بْنُ سَعِيدٍ، عَنْ أَبِي سَلَمَةَ، عَنْ أَبِي هُرَيْرَةَ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم مَنْ صَامَ رَمَضَانَ إِيمَانًا وَاحْتِسَابًا غُفِرَ لَهُ مَا تَقَدَّمَ مِنْ ذَنْبِهِ .
Narrated Abu Huraira: Allah's Messenger (ﷺ) 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."
Sahih al-Bukhari, 38Sahihصحيح