Sunan an-Nasa'i, Hadith 2213 ⓘ
It was narrated that Abu Saeed said: "The Prophet said: 'Allah, may He be blessed and exalted, says: Fasting is for me I shall reward for it. The fasting person has two moments of joy: When he breaks his fast and when he meets his Lord. By the One in Whose hand is the soul of Muhammad, the smell that comes from the mouth of the fasting person is better before Allah than the fragrance of musk." '
أَخْبَرَنَا عَلِيُّ بْنُ حَرْبٍ، قَالَ حَدَّثَنَا مُحَمَّدُ بْنُ فُضَيْلٍ، قَالَ حَدَّثَنَا أَبُو سِنَانٍ، ضِرَارُ بْنُ مُرَّةَ عَنْ أَبِي صَالِحٍ، عَنْ أَبِي سَعِيدٍ، قَالَ قَالَ النَّبِيُّ صلى الله عليه وسلم " إِنَّ اللَّهَ تَبَارَكَ وَتَعَالَى يَقُولُ الصَّوْمُ لِي وَأَنَا أَجْزِي بِهِ وَلِلصَّائِمِ فَرْحَتَانِ إِذَا أَفْطَرَ فَرِحَ وَإِذَا لَقِيَ اللَّهَ فَجَزَاهُ فَرِحَ وَالَّذِي نَفْسُ مُحَمَّدٍ بِيَدِهِ لَخُلُوفُ فَمِ الصَّائِمِ أَطْيَبُ عِنْدَ اللَّهِ مِنْ رِيحِ الْمِسْكِ " .
also referenced under: Book 22, Hadith 124 (In-Book) & Volume 3, Book 22, Hadith 2215 (DarusSalam)