Sahih Bukhari Volume 9, Book 90, Hadith Number 348.

Narrated By Abu Huraira : Allah’s Apostle forbade Al-Wisal. The people said (to him), “But you fast Al-‘Wisal,” He said, “Who among you is like me? When I sleep (at night), my Lord makes me eat and drink. But when the people refused to give up Al-Wisal, he fasted Al-Wisal along with them for two days and then they saw the crescent whereupon the Prophet said, “If the crescent had not appeared I would have fasted for a longer period,” as if he intended to punish them herewith.