The Day of the Covenant is the day when Bahá'ís celebrate the appointment of `Abdu'l-Bahá as the Centre of Baha'u'llah's Covenant. It occurs yearly on the 4th day of Speech (Qawl) which coincides with either November 25 or 26 depending on when Naw Ruz falls on that year. The 2016 date is November 25.
`Abdu'l-Bahá had stated that since May 23 was also the day that the Báb declared his mission, and should be exclusively associated with him, that that day should under no circumstances be celebrated as his day of birth. However, as the Bahá'ís begged for a day to be celebrated as `Abdu'l-Bahá's birthday, he gave them November 26, 181 days after the ascension of Bahá'u'lláh, to be observed as the day of the appointment of the Centre of the Covenant. The holiday was originally known as the Jashn-i-A’zam in Persian (The Greatest Festival), because `Abdu'l-Bahá was known as the Greatest Branch; in the West, the holy day became known as the Day of the Covenant.
The day is one of two Bahá'í holy days where work does not need to be suspended.