Although there is no scriptural account of a thirteenth month, such a month is none the less necessary.
Originally the cycle of the moon was assumed to be precisely 30 days, and precisely 12 cycles of the moon in a solar cycle of 360 days. The life span of men was also to be 1000 years. However, since the time of Noah, in fact from the time of Adam, there has been decay away from the Divine order through sin. Even the earth itself has been altered. Also the calendar determined by the movements of the celestial bodies is no longer a perfect fit:
Yehoshua spoke to YHVH and commanded the sun and moon to stand still, and they stopped almost an entire day. See Joshua 10:12-14
We have the account of Yeshayahu in prophecy to Hizkiyahu, calling the sun to move back 10 degrees (40 minutes) 2 Kings 20:8-11 and Yeshayahu (Isaiah) 38:7-8. We now have a lunar cycle 29 days, 12 hours, and 44 minutes and a solar cycle of 365 days, 5 hours and 48 minutes.
We can assume that the order will be restored in the final days as restoration comes before the return of the Messiah. We have the prophecy in the book of Revelation 11:2-3. The comparison of 42 months (the time of the Gentiles) with 1260 days, (the time of the two witnesses) corresponds exactly with 30 days per month. Furthermore the time of the woman in the wilderness, was also 1260 days. (Rev 12:6) We can assume this time to be three and a half years, three years and six months, half of seven years, or in the middle of seven years.
In the scripture there is no mention of a thirteenth month. The year is stated to have 12 months (Esther 3:7). We do however have this imbalance to deal with, of the solar year being approximately 11 days longer than 12 lunar months, and it has been dealt with very efficiently by the wise men of old who added a thirteenth month seven times in every nineteen solar cycles. It is essential that this month be inserted in order to keep in track of both the lunar and solar cycles, otherwise the seasons and our months would drift further and further back, (come earlier and earlier) each year totally out of line with the solar cycle. For example Passover must be held in the First month of the year, which must also be the spring, the “Aviv”.
May Yeshuah Moshiach soon return and restore all things.
As a result of this month being added there is only a Rosh Chodesh, a festival for a new moon and the weekly Sabbaths, but no other scriptural Holy days this month. The festival of Purim however, although mentioned in the book of Esther, (9:1: On the thirteenth day of the twelfth month, the month of Adar), is by tradition postponed from the twelfth to the thirteenth month whenever there is such an extra month. The important point is to remember, with sadness and perhaps with fasting as Esther did and also with great joy of celebration of the deliverance of the set apart people. May the Almighty be Praised.
Shalom and welcome to this presentation of what is a very ancient calendar system
