From Sahih Muslim (Hadith 2615):
Abu Sa'id al-Khudri (Allah be pleased with him) reported:We went out on an expedition with Allah's Messenger (ﷺ) on the 16th of Ramadan. Some of us fasted and some of us broke the fast. But neither the observer of the fast found fault with one who broke it, nor the breaker of the fast found fault with one who observed it
Reference: Muslim 2615