Allah states in the Quran (Surah At-Tawbah 9:36) that the year consists of 12 months, four of which are sacred (Al-Ashhur Al-Hurum): Muharram, Rajab, Dhul Qa'dah, and Dhul Hijjah. Fighting and wrongdoing are strictly prohibited, and good deeds carry multiplied rewards during these blessed months.

It is Sunnah to fast on the 13th, 14th, and 15th of every lunar Hijri month (known as Ayyam al-Beed or the White Days, when the moon is full). Additionally, fasting on Mondays and Thursdays throughout the year is highly recommended as deeds are presented to Allah on these days.

Ramadan is the 9th Hijri month in which daily fasting from dawn (Fajr) to sunset (Maghrib) is mandatory. Within its final 10 nights (specifically odd nights: 21st, 23rd, 25th, 27th, 29th) lies Laylat al-Qadr, a single night worth more than 1,000 months (83+ years) of continuous worship.

The Prophet Muhammad (ﷺ) taught that there are no days in which righteous deeds are more beloved to Allah than the first ten days of Dhul Hijjah. Fasting on the 9th day (Day of Arafah) expiates the sins of the previous year and the coming year for non-pilgrims.