The Book of Fasting - Sunan an-Nasa'i 2128

"The Messenger of Allah said: 'When you see the crescent then fast, and when you see it, then stop fasting. If it is too cloudy then complete Shaban as thirty days, unless you see the crescent before that, then fast Ramadan as thirty days, unless you see the new crescent before that."'

Commentary on the Lunar Sighting

This noble hadith establishes the fundamental principle that the beginning and end of Ramadan are determined by actual sighting of the crescent moon (hilal). The command "when you see" emphasizes physical observation as the primary means, reflecting the simplicity and practicality of Islamic law.

The Prophet ﷺ instructed visual confirmation rather than astronomical calculations, making the obligation accessible to all Muslims regardless of scientific knowledge. This approach fosters community involvement in this important religious observance.

The Cloudy Weather Provision

The exception for cloudy conditions demonstrates the wisdom of Islamic jurisprudence. When direct observation is impossible due to weather, Muslims are instructed to complete the previous month (Shaban) as thirty days. This provides a clear, practical solution that prevents uncertainty and maintains the lunar nature of the Islamic calendar.

Scholars explain that this completion to thirty days is a legal presumption (istiṣḥāb) that maintains continuity until visual evidence becomes available. This prevents the community from being paralyzed by uncertainty in fulfilling this important pillar of Islam.

Juridical Implications

This hadith forms the basis for the consensus among classical scholars that Ramadan begins with the verified sighting of the crescent moon. The ruling applies equally to ending Ramadan with the sighting of the Shawwal crescent.

The phrase "unless you see the crescent before that" indicates that if the moon is sighted before completing thirty days, the new month begins immediately. This preserves the lunar nature of Islamic months while providing clarity in implementation.