Mishkat al-Masabih #1869

He reported God’s messenger as saying, "Every and when the day of the fast of any of you comes he must not use vile language or raise his voice, and if anyone reviles him or tries to fight with him he should tell him he is fasting.” *This is not from the Qur’an, but is a hadith qudsi, a tradition which gives words spoken by God. (Bukhari and Muslim.)