Narrated Abu Huraira: Allah’s Messenger (peace be upon him) forbade Al-Wisal in fasting. So, one of the Muslims said to him, “But you practice Al- Wisal. O Allah’s Messenger (peace be upon him)!” The Prophet (peace be upon him) replied, “Who amongst you is similar to me? I am given food and drink during my sleep by my Lord.” So, when the people refused to stop Al-Wisal (fasting continuously), the Prophet (peace be upon him) fasted day and night continuously along with them for a day and then another day and then they saw the crescent moon (of the month of Shawwal). The Prophet (peace be upon him) said to them (angrily), “If It (the crescent) had not appeared, I would have made you fast for a longer period.” That was as a punishment for them when they refused to stop (practicing Al-Wisal).
Sahih al-Bukhari, Book 30, Hadith 72