Bukhari 4277

Narrated Ibn `Abbas:Allah's Messenger (ﷺ) set out towards Hunain in the month of Ramadan and some of the people were fasting while some others were not fasting, and when the Prophet (ﷺ) mounted his she-camel, he asked for a tumbler of milk or water and put it on the palm of his hand or on his she-camel and then the people looked at him; and those who were not fasting told those who were fasting, to break their fast (i.e. as the Prophet (ﷺ) had done so