«الصيام جنة من النار فمن أصبح صائما فلا يجهل يومئذ وإن امرؤ جهل عليه فلا يشتمه ولا يسبه وليقل إني صائم والذي نفس محمد بيده لخلوف فم الصائم أطيب عند الله من ريح المسك»
The Prophet (peace and blessings be upon him) said:
"Fasting is a shield from the Fire (for protection), so whoever begins the morning fasting should not act ignorantly that day, and if a man acts ignorantly towards him, he should neither abuse him nor revile him, but should say: 'I am fasting.' By the One in whose Hand is the soul of Muhammad! The smell of the fasting person's mouth is better with Allah than the fragrance of musk."
Hadith Referenceصحیح الجامع الصغیر / حرف الصاد / 3878