The Hebrew Calendar
“The heavens proclaim the glory of God; the skies display His craftsmanship”(Ps. 19:1, NLT).
The Gregorian calendar is the method for reckoning dates that most of the world uses. It was sponsored by Pope Gregory XIII in 1582 as a corrected version of the Julian calendar. It is a solar-based calendar in which dates indicate the position of the earth in its revolution around the sun.
The Hebrew/Jewish calendar is quite unlike the Gregorian or the Julian calendar. It is a modified lunar-based calendar—that is, it is based on cycles of the moon. It is also adjusted by adding intercalary months (that is, a thirteenth month in certain years)to bring the lunar cycles into synchronization with the solar year.
Trying to understand the holy day dates on the Gregorian calendar can be a bit challenging without at least a little knowledge of the Hebrew calendar. For example, the Feast of Trumpets (Rosh Hashanah) falls on the Hebrew calendar date of Tishri 1. One may wonder why in some years Tishri 1 may fall early in September, while in others; it may be as late as October.
(Chapter 7 is a description of the Day of Atonement, the Old Testament observance, te New Testmament significance and the prophetic implications.)