This brings us to the second synchronisation. In addition to the 'week', the Bible reveals a 49-year Sabbatic cycle starting New Year, 1st of Abib, following the previous block of forty-nine. They would have intercalated months as explained using the short cycle, until it reached the 7th month of the 49th year Then on the tenth day, a special 50th year was announced. This might seem strange but another astronomical formula is at work. The gap between the two events comes to 17718 days
- a figure equalling exactly 600 lunar months.
This gap never alters; it is always the same.
Now, 600 months equal 50 lunar years
which explains why the Jubilee fiftieth year is superimposed over the other years. It takes 48½ solar years to equal 50 lunar years, so the 'overlaid' Jubilee is a device that equalises the solar and lunar cycles to 50 years each, after which the new cycle began afresh. Let us take another hypothetical example from modern times. If we say 1st Nisan AD 1950 was the start of a cycle and count to the 7th month of the 49th year, it comes to 1st Tishri AD 1998, and 17718 days. Here are the dates:
1st Nisan .................. to .................. 1st Tishri
(19th March) ..... = 17718 days ....... (21st September)
1950 AD .......................................... 1998 AD
This formula is very precise, and may be observed from ancient times until now. I am not suggesting that we should continue to observe the old system or festivals. I'm just noticing that the calendar formulas still work. They works just as well today as they did in biblical times!
In summary, the pre-Metonic Hebrew calendar was a 7-year cycle of alternating 86 / 87 months, crosschecked by a long cycle of 600 months after 48½ years. Its distinguishing mark was a Sabbatical 'stamp' making it unique from every other national calendar.