Islamic holiday in the context of "Night of Power"

The Hijri calendar (Arabic: ٱلتَّقْوِيم ٱلْهِجْرِيّ, romanized: al-taqwīm al-hijrī), also known in English as the Islamic calendar, is a lunar calendar consisting of 12 lunar months in a year of 354 or 355 days. It is used to determine the proper days of Islamic holidays and rituals, such as the annual fasting and the annual season for the great pilgrimage. In almost all countries where the predominant religion is Islam, the civil calendar is the Gregorian calendar, with Syriac month-names used in the Levant and Mesopotamia (Iraq, Syria, Jordan, Lebanon and Palestine), but the religious calendar is the Hijri one.

This calendar enumerates the Hijri era, whose epoch was established as the Islamic New Year in 622 CE. During that year, Muhammad and his followers migrated from Mecca to Medina and established the first Muslim community (ummah), an event commemorated as the Hijrah. In the West, dates in this era are usually denoted AH (Latin: Anno Hegirae, lit. 'In the year of the Hijrah'). In Muslim countries, it is also sometimes denoted as H from its Arabic form (سَنَة هِجْرِيَّة, abbreviated ھ). In English, years prior to the Hijra are denoted as BH ("Before the Hijra").

The Day of Arafah (Arabic: يوم عرفة, romanized: Yawm ʿArafah) is an Islamic holiday that falls on the ninth day of Dhu al-Hijjah of the lunar Islamic calendar. It is the second day of the Hajj pilgrimage and is followed by the holiday of Eid al-Adha. At dawn of this day, Muslim pilgrims will make their way from Mina to a nearby hillside and plain called Mount Arafat and the Plain of Arafat in Saudi Arabia. It was from this site that the Islamic prophet Muhammad gave one of his last sermons in the final year of his life. Some Muslims hold that part of the Quranic verse announcing that the religion of Islam had been perfected was revealed on this day.