The Prophet (ﷺ) said: The month consists of twenty-nine days, but do not fast till you sight it (the moon) and do not break your fast till you sight it. If the weather is cloudy, calculate it thirty days. When the twenty-ninth of Sha'ban came, Ibn Umar would send someone (who tried) to sight the moon for him. If it was sighted, then well and good; in case it was not sighted, and there was no cloud and dust before him (on the horizon), he would not keep fast the next day. If there appeared (on the horizon) before him cloud or dust, he would fast the following day. Ibn Umar would end his fasting alone with the people, and did not follow this calculation.
Hadith Commentary: Moon Sighting for Ramadan
This narration from Sunan Abi Dawud 2319 in the Book of Fasting (Kitab Al-Siyam) establishes the fundamental Islamic principle of physical moon sighting (ru'yah) for determining the beginning and end of Ramadan. The Prophet (ﷺ) explicitly prohibited mathematical calculation alone for this sacred obligation, emphasizing visual confirmation as the primary method.
Scholarly Analysis of the Text
The command "do not fast till you sight it" indicates the act of fasting is contingent upon actual moon sighting, not mere calendar calculations. This preserves the unity of the Muslim community (ummah) in beginning and ending their worship simultaneously.
The exception for cloudy weather - "calculate it thirty days" - refers to completing Sha'ban as thirty days, not astronomical calculation. This ensures we err on the side of caution in matters of worship.
Practical Application by Ibn Umar
Ibn Umar's meticulous practice demonstrates the companions' strict adherence to the Prophetic methodology. His personal effort to sight the moon, even sending others, shows the importance given to this religious duty.
His refusal to fast if the moon wasn't sighted on a clear 29th day, while fasting if clouds obstructed vision, perfectly implements the Prophet's instructions. His concluding practice of ending fasting with the community highlights the importance of collective unity over individual opinion.
Legal Implications
Classical scholars unanimously agree this hadith establishes moon sighting as the primary method for determining Ramadan. The majority position maintains that calculation cannot override actual sighting, though some later scholars permitted calculation as a supplementary means in certain circumstances.
The wisdom behind this method includes maintaining the simplicity of Islamic worship, preserving communal unity, and keeping the religion accessible to all Muslims regardless of educational background.