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).
Hadith Text & Reference
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)."
Source: Sunan Abi Dawud 2326 | Book: Fasting (Kitab Al-Siyam)
Legal Ruling & Prohibition
This hadith establishes the fundamental principle that Ramadan fasting must not commence based on mere calculation or assumption. The beginning and end of Ramadan are determined exclusively through actual moon sighting or completing thirty days of Sha'ban if the moon is obscured.
Scholars emphasize this prohibition guards against two errors: initiating fasting too early based on uncertainty, and ending it prematurely without proper evidence. The command preserves the sanctity of divinely prescribed timings.
Methodology of Moon Sighting
Classical scholars interpret "sighting the moon" as visual confirmation by trustworthy Muslim witnesses. If clouds prevent sighting, thirty days of Sha'ban are completed before commencing Ramadan fasting.
The same methodology applies to ending Ramadan: Eid is declared either through moon sighting for Shawwal or by completing thirty days of fasting. This eliminates speculation and ensures unified community practice.
Wisdom & Objectives
This ruling preserves the lunar nature of Islamic worship, maintaining connection to natural phenomena as Allah's signs. It prevents division within the Muslim community by establishing clear, observable criteria.
The methodology ensures worship remains accessible to all Muslims regardless of astronomical knowledge, emphasizing practical implementation over theoretical calculation in matters of worship.