Among the most consistent voluntary practices of the Prophet Muhammad (peace be upon him) was his fasting on Mondays and Thursdays. This weekly observance is a Sunnah mu’akkadah – an emphasized recommended practice – not an obligation, and it is preserved in multiple authentic chains across the canonical hadith collections.

The reason the Prophet (peace be upon him) gave for these particular days is preserved in Jami at-Tirmidhi 747: “Deeds are presented [to Allah] on Mondays and Thursdays, and I love that my deeds be presented while I am fasting.” A complementary narration in Sahih Muslim 2634 records that when the Prophet was asked about fasting on Monday, he answered: “That is a day on which I was born and on which I was sent [as a Prophet], and on which the Qur’an was revealed to me.”

Practically, this fast follows the same rules as any other voluntary day fast in Islam: abstention from food, drink, and marital relations from the true dawn (fajr) until sunset (maghrib), with the intention formed before fajr or by the morning if no food has been taken. The fast may be broken with a date and water at sunset, following the Prophet’s general practice for breaking the fast, and is followed by the Maghrib prayer.

The Monday-Thursday fast is closely linked to the broader practice of voluntary fasting in Islam, which also includes the three White Days of every Hijri month, the Day of Arafah, the Day of Ashura, and the six days of Shawwal. Many of the Companions of the Prophet (may Allah be pleased with them) combined these practices. There is no contradiction between observing the weekly fast and the monthly White Days; in months where the dates overlap, the single day counts for both intentions.

Days on which fasting is explicitly forbidden – the two Eids and the Days of Tashriq– supersede this practice. If a Monday or Thursday falls on one of these prohibited days, the fast is not observed. Otherwise, the weekly fast is a steady, low-friction way to anchor a rhythm of worship into the ordinary week.