Genesis 1:14 says:
Then God said, "Let there be lights in the firmament of the heavens to divide the day from the night; and let them be for signs and for seasons, and for days and years".
This clearly defines the 4 roles of the sun, moon and stars:
- To divide the day from the night
- For signs
- For seasons (Hebrew "moed" meaning appointed times)
- For days and years - ie for calendars
The first calendar was lunar based
Different calendars variously use the moon and the sun and we describe them as lunar or solar, or sometimes lunisolar if they are based on both the sun and the moon. Later Jewish calendars are lunisolar. They are basically lunar calendars that also keep in line with the sun to maintain the calendar years in their solar seasons for agricultural purposes.
However, before the flood the Bible indicates there was a vapour canopy over the earth - the "waters which were above the firmament" (Genesis 1:7). This probably produced what today we would call a "greenhouse effect" in which there were no distinct solar seasons. Therefore, it is likely that the first Biblical calendar from creation to the flood was simply lunar based...
- A lunar month (a lunation, the time between new moons) is just over 29½ days
- 12 lunations gives a lunar year of just over 354 days (12 x 29½ = 354)
Before the water canopy collapsed at the flood, it was probably impossible to see the crescent of the new moon. There would only have been a monthly cycle of brighter and darker nights according to the phase of the moon. For simplicity, as our calculation above shows, it is likely that the calendar had 354 days.
Calendar of families
This calendar was used during the period of history when God administered the affairs of mankind in families, before the population of the earth was divided into nations.
Jubilee principle
When God introduced Jubilee Years to Israel after the Exodus, the calendar had become lunisolar. The Jubilee was sounded on the 10th day of the 7th month of the 49th year, when there had been:-
- 48 years of 12 lunations (the time between new moons),
- 18 intercalations (extra months added to keep the lunar year in line with the solar seasons),
- 6 lunations in the 1st half of the 49th year.
[(48 x 12) + 18 + 6] = 600 lunations
= 50 lunar years of 12 lunations each year.
In other words, when the Jubilee was sounded in the lunisolar calendar after the Exodus, 50 lunar years had already been completed in the lunar calendar that had been running since creation week! The principle of the Jubilee:
- each 49 year cycle in man's eyes was regarded as 50 years in God's eyes
When the Jubilee was sounded, 50 354-day lunar years had been completed!
