The obligation is held by Sunni and Shia alike, with the schools differing chiefly on technical points such as the precise moment at which the fast may be broken each evening, Shia jurisprudence generally requiring a slightly later confirmation of sunset than most Sunni practice. Beyond physical abstention, the tradition stresses restraint of speech and conduct, additional night prayers, tarawih in the Sunni congregational form, and heightened charity, and it fixes the month's climax in the last ten nights, when Laylat al-Qadr, the Night of Power commemorating the Quran's revelation, is sought, and some believers undertake itikaf, a period of retreat in the mosque.
The month ends in the festival of Eid al-Fitr, marked by communal prayer, the giving of a specific charity (zakat al-fitr) intended to let the poor share in the celebration, and shared meals that, in many cultures, have grown into the month's most visible social institution, the nightly iftar gathering that breaks each day's fast.
As one of the Pillars, Ramadan belongs with the other defining acts of Muslim devotion, and its emphasis on self-restraint as a school for piety invites comparison with fasting disciplines elsewhere, such as the Christian observance of Lent; the traditions differ sharply in form and length, but both frame renewed physical discipline as the route to a renewed inward state, a pattern common enough across religious fasting that scholars of comparative religion treat it as one of the recurring shapes ascetic practice takes.