When any one of you gets up in the morning in the state of fasting, he should neither use obscene language nor do any act of ignorance. And if anyone slanders him or quarrels with him, he should say:" I am fasting, I am fasting." (Using translation from Muslim 1151a)   

«إِذَا أَصْبَحَ أَحَدُكُمْ يَوْمًا صَائِمًا فَلَا يَرْفُثْ وَلَا يَجْهَلْ فَإِنِ امْرُؤٌ شَاتَمَهُ أَوْ قَاتَلَهُ فَلْيَقُلْ إِنِّي صَائِمٌ وَإِذَا دُعِيَ أَحَدُكُمْ إِلَى طَعَامٍ وَهُوَ صَائِمٌ فَلْيَقُلْ إِنِّي صَائِمٌ»