One of the most surprising aspects of the Book of Jubilees is how much of it is about the calendar. This isn't a minor theological footnote — it's central to the entire book's purpose. According to Jubilees, God revealed to Moses on Sinai not just the Law but also the precise calendar by which all sacred observances should be kept. And that calendar, Jubilees insists, has been corrupted and forgotten.
The Jubilees calendar is solar — 364 days divided into four seasons of 91 days each, with each season beginning on the same day of the week. This is opposed to the lunar calendar used by most of the ancient Near East, and eventually adopted by mainstream Judaism. According to Jubilees, the lunar calendar is a gentile corruption that causes Israel to observe festivals on the wrong days.
The stakes are high: if you observe Passover or Yom Kippur on the wrong day, you're not observing it at all. You're profaning the sacred times God established. The community at Qumran — the Dead Sea Scrolls community — used the Jubilees calendar for exactly this reason. They believed mainstream Judaism had gone wrong by following the moon instead of the sun.
Whether you accept Jubilees' calendar theology or not, the text raises profound questions about how we measure sacred time and whether the religious calendars we've inherited are the ones God intended.
Our collector's edition of the Book of Jubilees includes the complete text with annotations covering the calendar system and its significance.