Smak bin Hrb bin Aws سماك بن حرب بن أوس · Fasting (Kitab Al-Siyam)

The Prophet (ﷺ) said: Do not fast (for Ramadan) before the coming of the month until you sight the moon or complete the number (of thirty days); then fast until you sight the moon or complete the number (of thirty days).

On the authority of a man from the Companions of the Prophet (ﷺ): People differed among themselves on the last day of Ramadan (about the appearance of the moon of Shawwal). Then two bedouins came and witnessed before the Prophet (ﷺ) swearing by Allah that they had sighted moon the previous evening. So the Messenger of Allah (ﷺ) commanded the people to break the fast. The narrator Khalaf has added in his version: "and that they should proceed to the…

A bedouin came to the Prophet (ﷺ) and said: I have sighted the moon. Al-Hasan added in his version: that is, of Ramadan. He asked: Do you testify that there is no god but Allah? He replied: Yes. He again asked: Do you testify that Muhammad is the Messenger of Allah? He replied: Yes. and he testified that he had sighted the moon. He said: Bilal, announce to the people that they must fast tomorrow.