From Sahih Muslim (Hadith 2604):
Ibn Abbas (Allah be pleased with him) reported that the Messenger of Allah (ﷺ) went out during the month of Ramadan in the year of Victory (when Mecca was conquered) and was fasting till he reached Kadid (a canal situated at a distance of forty-two miles from Mecca) and he then broke the fast. And it was the habit of the Companions of the Messenger of Allah (ﷺ) to follow him in every new thing (or act). So they followed him also (in this matter)
Reference: Muslim 2604