It is narrated from Hazrat Abu Huraira (may Allah be pleased with him) that the Holy Prophet (peace and blessings be upon him) said: When any one of you is fasting, he should not utter any abusive or foul words, and if someone wants to fight or abuse him, he should simply say, "I am fasting."
Hadith Referenceمسند احمد / مسند المكثرين من الصحابة / 9532
Hadith Gradingحکم دارالسلام:حدیث صحیح ، وھذا إسناد حسن ، خ : 1894 ، م : 1151