Chapter: If a fasting person is invited to eat and he does not want to break his fast, or someone insults him or argues with him, it is recommended for him to say: I am Fasting, and he should protect his fast from obscene speech, ignorance and the like

Hadith Number 1150

setting

Abu Huraira (Allah be pleased with him) reported Allah's Apostle (ﷺ) as saying

If any one of you is invited to a meal when he is fasting, he should say:" I am fasting."