Musnad Abu Ya'la al-Mawsili 109:130

Ishaq narrated to us, Abd al-Aziz ibn Muhammad narrated to us, from Ja'far ibn Muhammad, from his father, from Jabir: That the Messenger of Allah (ﷺ) went out to Makkah in the year of the Conquest in Ramadan. He fasted until he reached Kura' al-Ghamim, and he fasted Ramadan, and the people fasted with him. It was said to him, "The fasting has become difficult for the people, and they are only looking at what you do." So he called for a cup of water after the afternoon (Asr), and he drank while the people were looking. Then some of the people fasted and some broke their fast. It reached him that some people had fasted, so he said, "Those are the disobedient ones."