Abu Hurairah (May Allah be pleased with him) reported:
The Messenger of Allah ﷺ said, "When any one of you is observing Saum (fasting) on a day, he should neither indulge in obscene language nor should he raise the voice; and if anyone reviles him or tries to quarrel with him he should say: 'I am observing fast."'

[Al-Bukhari and Muslim].

عن أبي هريرة رضي الله عنه قال: قال رسول الله ﷺ: "إذا كان يوم صوم أحدكم فلا يرفث ولا يصخب، فإن سابه أحد أو قاتله، فليقل: إني صائم"