Why do Muslims fast in Ramadan?

The command and its stated purpose arrive together: “O you who have believed, decreed upon you is fasting as it was decreed upon those before you that you may become righteous -” (Qur’an 2:183)

That last phrase is the whole answer. Fasting is not an endurance test and not a penance — it is training in preferring what Allah wants over what you want, practised on something as basic as food so that it transfers to things that are harder.

The month is specified because of what happened in it: “The month of Ramaḍān is that in which was revealed the Qur’ān, a guidance for the people and clear proofs of guidance and criterion. So whoever sights the crescent of the month, let him fast it; and whoever is ill or on a journey - then an equal number of other days. Allah intends for you ease and does not intend for you hardship and wants for you to complete the period and to glorify Allah for that to which He has guided you; and perhaps you will be grateful.” (Qur’an 2:185)

A few things about it that surprise people:

• It is not only abstaining from food and drink. It also includes intimacy during daylight hours, and — as importantly — restraint of speech and temper.
• It moves. The Islamic calendar is lunar, so Ramadan shifts about eleven days earlier each year and passes through every season over a lifetime. Nobody is permanently stuck with the long summer fasts.
• It is communal in a way little else is. Whole families and neighbourhoods eat at the same minute, and that shared rhythm is much of what people end up loving about it.
• It ends in ‘Īd al-Fitr, a day on which fasting is actually forbidden.

Most people find the first three days hard and then adjust. The reported experience across the tradition, and from most Muslims you ask, is that the month feels short by the end and is missed when it goes.