Abu Huraira and Abu Sa'id (Allah be pleased with both of them) reported Allah's Messenger (ﷺ) (as saying): Allah, the Exalted and Majestic, said: Fast (is exclusively) meant for Me and I would give its reward. There are two (occasions) of joy for the observer of fast. He feels joy when he breaks the fast and he is happy when he meets Allah. By Allah in Whose Hand is the life of Muhammad, the breath of the observer of fast is sweeter to Allah than the fragrance of musk.
Source: sunnah.com
Other translations
Arabic
وَحَدَّثَنَا أَبُو بَكْرِ بْنُ أَبِي شَيْبَةَ، حَدَّثَنَا مُحَمَّدُ بْنُ فُضَيْلٍ، عَنْ أَبِي سِنَانٍ، عَنْ أَبِي، صَالِحٍ عَنْ أَبِي هُرَيْرَةَ، وَأَبِي، سَعِيدٍ - رضى الله عنهما - قَالاَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " إِنَّ اللَّهَ عَزَّ وَجَلَّ يَقُولُ إِنَّ الصَّوْمَ لِي وَأَنَا أَجْزِي بِهِ إِنَّ لِلصَّائِمِ فَرْحَتَيْنِ إِذَا أَفْطَرَ فَرِحَ وَإِذَا لَقِيَ اللَّهَ فَرِحَ . وَالَّذِي نَفْسُ مُحَمَّدٍ بِيَدِهِ لَخُلُوفُ فَمِ الصَّائِمِ أَطْيَبُ عِنْدَ اللَّهِ مِنْ رِيحِ الْمِسْكِ " .
sunnah.com