It is narrated from Sayyiduna Abdullah bin Mas'ud (may Allah be pleased with him), as a marfu' report, that the Prophet (peace and blessings be upon him) said: "The fasting person has two joys: a joy at the time of breaking his fast, and a joy when he meets his Lord. And the odour of the fasting person's mouth is more pleasing to Allah than the fragrance of musk."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 10041