Sayyiduna Jabir (may Allah be pleased with him) said that the Prophet (peace and blessings be upon him) set out in Ramadan in the year of the Conquest and fasted until he reached Kura' al-Ghamim, and the people fasted with him (peace and blessings be upon him). It was said: O Messenger of Allah, fasting has become hard for the people. So he (peace and blessings be upon him) called for a cup of water after Asr and drank it while the people were watching. Some of them broke their fast and some did not. Then it reached him (peace and blessings be upon him) that some people were still fasting, and he (peace and blessings be upon him) said: "Those are the disobedient ones."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصيام / 8146