The Messenger of Allah ﷺ said, "When it is the day of fasting for any of you, let him not engage in obscene speech or behave ignorantly. If anyone behaves ignorantly toward him, let him say, 'I am a man who is fasting.'"
حدثنا ابن نمير قال أخبرنا الأعمش عن أبي صالح
قال رسول الله ﷺ إذا كان يوم صوم أحدكم فلا يرفث ولا يجهل فإن جهل عليه أحد فليقل إني امرؤ صائم
Its chain of transmission is sahih, it was mentioned previously at 7827 and 10088.10378 (duplicate) - And with the same chain, "Leave me be as long as I leave you be, for those before you were destroyed only because of their excessive questioning and their disputing with their prophets. So when I command you with something, do as much of it as you can, and when I forbid you from something, refrain from it." Sahih (10378 duplicate). Its chain of transmission is sahih, it was mentioned previously at 7361 and 10204.