Sahih Muslim
The Book of Fasting (Kitab Al-Sawm)
Book Number: 006 / Hadith Number: 2479
Abu Sa'id al-Khudri (Allah be pleased with him) reported: We went out on an expedition with the Messenger of Allah (may peace be upon him) during Ramadan and neither the observer of the fast was found fault with for his fasting, nor the breaker of the fast for breaking it.