What a fasting person should say when reviled

"Truly, I am fasting! Truly, I am fasting!"

The Prophet ﷺ said: "Fasting is a shield. When one of you is fasting, let him not utter obscenities or shout; and if anyone reviles or attacks him, let him say: ‹Truly, I am fasting!›" [al-Bukhari 1894; Muslim 2703].

[al-Bukhari 1894; Muslim 2703]