The Qumran Community
---The True Calendar
“They shall be neither early nor late for any of their appointed times” (Community Rule I, 14–15)
The Qumran sectarians believed that God had granted them knowledge of profound cosmological secrets, including knowledge of the true calendar and the exact times of the festivals. In their view, strict obedience to this calendar was a primary religious duty.
The sectarian calendar was based on the heavenly course of the sun and consisted of 364 days. These were divided into twelve months, each comprising 30 days except for the third, sixth, ninth, and twelfth months, which had 31 days. Festivals always fell on the same day of the week: Passover on Wednesday, the Feast of Weeks (Shavuot) on Sunday, and the Day of Atonement (Yom Kippur) on Friday. The origins of this calendar lay in an ancient Jewish tradition (mentioned, for example, in the pseudepigraphical Book of Jubilees and First Book of Enoch); some scholars believe that it was even used in the land of Israel in the First Temple period.
In contrast to the Judean Desert sectarians, the priestly establishment in Jerusalem followed the lunisolar calendar that had been adopted by Antiochus Epiphanes in 167 BCE. Some authorities feel that the controversy surrounding the calendar was one of the decisive motives for the sect’s decision to leave Jerusalem.