2. Īmān (Faith / Belief)

٢۔ كتاب الإيمان

Bukhārī > Chapter 2 > Section 29
البخاري > كتاب ٢ > باب ٢٩

2.29 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

٢۔٢٩ باب صَوْمُ رَمَضَانَ احْتِسَابًا مِنَ الإِيمَانِ

All sins forgiven for the one who sincerely fasts Ramadan

bukhari:38 – Ibn Salām > Muḥammad b. Fuḍayl > Yaḥyá b. Saʿīd > Abū Salamah > Abū Hurayrah

Messenger of Allah 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."  

البخاري:٣٨ – حَدَّثَنَا ابْنُ سَلاَمٍ قَالَ أَخْبَرَنَا مُحَمَّدُ بْنُ فُضَيْلٍ قَالَ حَدَّثَنَا يَحْيَى بْنُ سَعِيدٍ عَنْ أَبِي سَلَمَةَ عَنْ أَبِي هُرَيْرَةَ قَالَ

قَالَ رَسُولُ اللَّهِ ﷺ مَنْ صَامَ رَمَضَانَ إِيمَانًا وَاحْتِسَابًا غُفِرَ لَهُ مَا تَقَدَّمَ مِنْ ذَنْبِهِ