The Kitáb-i-Aqdas

This passage establishes four great festivals of the Bahá’í year. The two designated by Bahá’u’lláh as “the two Most Great Festivals” are, first, the Festival of Riḍván, which commemorates Bahá’u’lláh’s Declaration of His Prophetic Mission in the Garden of Riḍván in Baghdád during twelve days in April/May 1863 and is referred to by Him as “the 225 King of Festivals” and, second, the Báb’s Declaration, which occurred in May 1844 in Shíráz. The first, ninth and twelfth days of the Festival of Riḍván are Holy Days (Q and A 1), as is the day of the Declaration of the Báb.

The “two other Festivals” are the anniversaries of the births of Bahá’u’lláh and the Báb. In the Muslim lunar calendar these fall on consecutive days, the birth of Bahá’u’lláh on the second day of the month of Muharram 1233 A.H. (12 November 1817), and the birth of the Báb on the first day of the same month 1235 A.H. (20 October 1819), respectively. They are thus referred to as the “Twin Birthdays” and Bahá’u’lláh states that these two days are accounted as one in the sight of God (Q and A 2). He states that, should they fall within the month of fasting, the command to fast shall not apply on those days (Q and A 36). Given that the Bahá’í calendar (see notes 26 and 147) is a solar calendar, it remains for the Universal House of Justice to determine whether the Twin Holy Birthdays are to be celebrated on a solar or lunar basis.