Sahih al-Bukhari 7538
Sahih al-Bukhari · Book 97: Oneness, Uniqueness of Allah (Tawheed) · What the Prophet (saws) mentioned and narrated of his Lord’s Sayings
Narrated Abu Huraira:
حَدَّثَنَا آدَمُ ، حَدَّثَنَا شُعْبَةُ ، حَدَّثَنَا مُحَمَّدُ بْنُ زِيَادٍ ، قَالَ سَمِعْتُ أَبَا هُرَيْرَةَ ، عَنِ النَّبِيِّ صلى الله عليه وسلم يَرْوِيهِ عَنْ رَبِّكُمْ، قَالَ " لِكُلِّ عَمَلٍ كَفَّارَةٌ، وَالصَّوْمُ لِي وَأَنَا أَجْزِي بِهِ، وَلَخَلُوفُ فَمِ الصَّائِمِ أَطْيَبُ عِنْدَ اللَّهِ مِنْ رِيحِ الْمِسْكِ " .
The Prophet (ﷺ) said that your Lord said, "Every (sinful) deed can be expiated; and the fast is for Me, so I will give the reward for it; and the smell which comes out of the mouth of a fasting person, is better in Allah's Sight than the smell of musk." (See Hadith No. 584)