Genesis Chapter 1: v.1-Chapter 6: v. 8
LA JOLLA, California — The reading opens with the Hebrew story of the world’s creation. which text claims to have taken God six ‘biblical’ days, following which He rested on the seventh day.
Later in the Torah, we read two versions of the Fourth Commandment, which is to observe the Sabbath. In Exodus, Chapter 20: vv. 8-11, we are commanded to rest on each week’s seventh day, because God rested on and blessed that day. In Deuteronomy, Chapter 5: vv. 12-15, this version commands rest because you were slaves in Egypt, and God freed you.
My curiosity is over the origin of the seven-day week. Understandably days, years, and months are marked by astronomical events. Days are measured by sunset to sunset, or dawn to dawn. Years are derived from the annual cycle of the sun. Months are derived from the 29 &1/2 day cycle of the moon, simplified via reduction to a unified 28 days per month, plus addition of leap years to periodically accommodate the growing overage of days.
The seven-day week doesn’t apparently have an astronomical connection. Historically, scholars have considered the week to be a Hebrew invention, derived from its creation story.
However, the ancient predecessor Babylonians (2000-1000 BCE) did have a seven-day week, admittedly unrelated to rest. They marked time with lunar months, but they divided each month into four components. The new moon and the full moon were obvious, but they considered also the seventh day, i.e. the waxing half-moon, and the 21st day, i.e. the waning half-moon also as intervals. Thus they created a seven-day cycle. Like the later Hebrews, they considered each day to begin at sundown. The pagan Babylonians considered each seventh day to be holy, but also to be unlucky. Accordingly they applied restrictions those days on certain activities, to avoid dire consequences.
Also to be noted is that, as well as astronomy, they were advocates of astrology/mysticism. Accordingly they assigned names to each of the seven days from what they believed were the seven non-fixed celestial bodies visible to the naked eye. These were the Sun, Moon, Mars, Mercury, Jupiter, Venus, and Saturn. From these, they proceeded to invent a non-scientific horoscope system.
The ancient Romans, in their early days as a Republic, actually had an eight-day week, the reasons unknown to us. Later, as an Empire, when they adopted Christianity under emperor Constantine (~320 AD), Rome adopted the Biblical seven-day week. [1],[2],[3],[5]