Page 27 - Advanced OT Survey Student Textbook

How did they keep track of time in Genesis?

As you well know, most countries today operate on the Gregorian Calendar which is based on the
rotation of the earth around the sun which is make up of 365.25 days per year. Every fourth year, we
add a day to February to synchronize the once again the rotation around the sun. However, the
Gregorian calendar which we use today is a relatively recent invention of Pope Gregory XIII in 1582.
Before that, most of the world used the Julian calendar which fell out of sync with the solar year by 11
minutes each year. Continued use of the Julian calendar meant that the seasons of the year were no
longer synchronized with the months and days. Pope Gregory primarily was concerned that Easter,
which was always observed on March 21 of each year, fell further away from the spring equinox as each
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year passed.

In the ancient times, people tracked days by a lunar calendar following the lunar cycles. The lunar
month has about 29.5 days in a month or about 354.4 days in a solar year. To make up the 11-day
difference and keep the calendar synchronized with the seasons, the Hebrew calendar has periodic leap
years, which add an extra 30-day month to the end of the year. The leap year occurs about once every
three years.

The Hebrew years begin counting from the moment of creation as interpreted from the Torah. This
number is determined by adding the ages of people in the Bible back to creation (about our 4000 BC).
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To find a corresponding Hebrew date from a Gregorian year, add 3760 years to the Gregorian date.

We don’t really know how Adam and his near relatives kept track of the dates and years, but obviously
by the time of Moses, they had established a system based on the lunar cycle. God, in Genesis 1,
created time and set the rotation of the earth, creating night and day. Notice that during the creation
week, each day was defined by saying, “And the evening and morning were the xxx day.” (Genesis 1:19).
God defined a day to start in the evening when the moon become visible, and then continue the day
through the day light to the next evening (around 6:00 PM). God by example also established the length
of a week, by resting on the seventh day. The first mention of years in the Bible was in Genesis 5:3
where the age of Adam is recorded when he begat Seth, 130 years.

The length of a day is extremely important to understand when reading the Bible. From the beginning
of time and throughout the history of Israel, the Jewish people have been keeping track of time based
on a lunar cycle. The Jewish day begins at dusk, usually measured by the appearance of three medium
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sized stars in the sky, but the exact time is a question of debate amongst early Rabbis. And of course,
the season of the year would determine when dusk time might be. But in the Jewish mind, especially
when considering the Feast Days or Sabbath days, the Jewish day started in the evening of one day and
ended the evening of the next day.

So why is this significant? In our way of thinking about days, we think of an event occurring on a certain
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day of the week. For example, Christmas is on December 25 . It starts at 12:00 AM but we are sleeping,
so Christmas day in our mind is from morning when we get up to the evening when we go to bed. But in
the Jewish mind, a day begins in the evening as the sun is setting. It continues until they go to bed and
rise in the morning, until the dusk of the day. So, a Hebrew day in the Bible can actually cover two of
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our days. In the Jewish mind, Christmas would begin on our 24 in the evening, and conclude on the
25 at dusk, or around 6 PM.
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25 https://www.history.com/news/6-things-you-may-not-know-about-the-gregorian-calendar
26 https://www.reference.com/science/hebrew-calendar-differ-gregorian-calendar-6c15ba0ba5140478
27 https://www.yeshiva.co/ask/7469
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