Sunan an-Nasa'i 2212

أَخْبَرَنَا مُحَمَّدُ بْنُ بَشَّارٍ، قَالَ حَدَّثَنَا مُحَمَّدٌ، قَالَ حَدَّثَنَا شُعْبَةُ، عَنْ أَبِي إِسْحَاقَ، عَنْ أَبِي الأَحْوَصِ، قَالَ عَبْدُ اللَّهِ ‏ "‏ قَالَ اللَّهُ عَزَّ وَجَلَّ الصَّوْمُ لِي وَأَنَا أَجْزِي بِهِ وَلِلصَّائِمِ فَرْحَتَانِ فَرْحَةٌ حِينَ يَلْقَى رَبَّهُ وَفَرْحَةٌ عِنْدَ إِفْطَارِهِ وَلَخُلُوفُ فَمِ الصَّائِمِ أَطْيَبُ عِنْدَ اللَّهِ مِنْ رِيحِ الْمِسْكِ ‏"‏ ‏.‏

It was narrated from Abu Al-Ahwas that 'Abdullah said:"Allah, may He be exalted, said: 'Fasting is for me and I shall reward for it. The fasting person has two moments of joy: When he breaks his fast and when he meets his Lord. And the smell that comes from the mouth of the fasting person is better before Allah than the fragrance of musk

Reference

Sunan an-Nasa'i 2212

In-book

Book 22, Hadith 123