Why the WEEK?

What is the real origin of the universal seven-day rhythm of human life? Why are our calendars set up into seven day groups? Why are most TV shows aired every seven days instead of every four or five? And why is it easy enough to mistake a Tuesday for a Wednesday, but almost impossible to mistake a Friday for a Saturday?

These questions point to something so pervasive, so universal, and so deeply entrenched in our lives that we take it for granted: the seven-day week. Next to the day, the week is the most important calendar unit in our lives.

How did this seven-day cycle come to so conspicuously occupy our minds and our calendars? Where did it originate and become such a rhythm in our human lives?

Most other major measurements of time are determined by what happens in the skies above us. The length of a year is determined by how long it takes our planet to make one full revolution around the sun. The month is based on the time required for our moon to complete its cycle. A day is the time the Earth takes to complete one full rotation on its axis.

But what about the week? What astronomical cycle determines this seven-day span?

Divided Lunar Cycle Theory

One common explanation says the week is based on one quarter of the 29.5-day lunar cycle, which would come to nearly 7.4 days. Proponents say ancient peoples used the moon’s cycle to determine the duration of both the month, in its complete cycle, and the week, as one quarter of that cycle. The early Babylonians did have a calendar in which each month began on a new moon and was separated into four 7-day segments followed by one or two odd days each month.

But the week is essentially defined as a precise multiple of the day, quite independently of the lunar month. And any subdivision of the lunar cycle necessarily involves some mathematically inconvenient remainder of hours, minutes and seconds.

The divided lunar cycle theory also does not explain the fact that, in almost all societies, the week is seven days longs. After all, a lunar month could just as easily be divided into three 10-day sections, or five 6-day blocks, six 5-day spans. Why would early societies choose to divide the lunar cycle by four? The number is arbitrary.

Visible Celestial Bodies Theory

Another explanation for the week comes from adding up the number of celestial bodies in our solar system that are visible with the naked eye. The sun, the moon, Mercury, Venus, Mars, Jupiter and Saturn would all have been visible to early stargazers who had no telescopes, so the sum is seven.

It is undeniable that the days of the week on our calendars (in English and European languages) are named after the visible bodies. However, the facts of history prove that the seven-day week existed long before its days came to be associated with heavenly bodies or with ancient gods. Seven-day observance had been established long before the astrological week ever came into being with its naming of the days of the week.

Thus the visible celestial bodies theory doesn’t explain the week’s origins any better than the divided lunar theory. History and logic easily disprove both of these theories and reveal how weak they really are.

An Invention of Ancient Israel?

Some conclude that the seven-day week was the invention of ancient Israel, and that it eventually spread from that early society into the whole world. The trouble with this theory, though, is that biology proves the seven-day week predates all societies.

Mankind has long understood that our bodies operate on circadian (daily), monthly and annual rhythms, but chronobiologists have only recently discovered seven-day patterns written into the biology of people, animals and plants. They have found that the blood pressure cycle, hormone cycles, immune responses to infections, production of blood and urine chemicals, and even the heartbeat operate on a seven-day pattern.

Seven-day cycles also govern fundamental aspects in the lives of flies, rats and other critters. And researchers have uncovered no cycles that occur in five, six, eight, nine or any other number of days – only seven.

The Week’s True Origins

The week is completely oblivious to seasons, tides, orbits and every other aspect of external nature. Nothing in the cosmos happens in seven days, so there is no astronomical reason for the week. So the week had to originate from another source. Science proves that the seven-day cycle is also etched deeply into mankind’s DNA, proving it could not have been the invention of any society.

The intelligentsia of the world have strained in vain to attribute the week’s origins to something secular, but it cannot be done.

THAT IS BECAUSE THE WEEK WAS CREATED BY GOD.

The first two chapters of the book of Genesis detail God’s creation of the universe. It speaks of “days” of creation with God resting on the seventh “day”. Some biblical scholars say that these were actual 24 hour days. Others say that these “days” were actually long but definable periods of time beginning with the Big-Bang 14 billion years ago.

For our discussion, the point to be made in Genesis is that there IS a seven day cycle ending with God resting on the seventh day. God then commanded His people to rest on each seventh day of the seven-day cycle from then on as an external tribute to God’s creation and rest (Exodus 20:8-11; 31:15-17). So, almost as a byproduct of the work He accomplished during the seven “days” of creation, God also created the WEEK.

In Mark 2, Jesus Christ says, “the Sabbath was made for man.” Leviticus 23:3 says, “Six days shall work be done, but the seventh day is the Sabbath of rest, a holy convocation; you shall do no work therein.” So, it was not just the Sabbath but the entire seven-day week that was actually made for men. The command to labor for six days is every bit as clear as the command to rest on the seventh. And Christ did not say this model is just for Jews or Israelites, but for “man”, or all mankind.

Some societies have experimented with “weeks” longer than seven days. In 1793, just after the French Revolution, France adopted a 10-day week. The revolutionaries made the move in an effort to simultaneously de-Christianize the country and increase its productivity. But France only kept the 10-day week around for 12 years because of its extremely disappointing results. During these years, French society saw a stark increase in injuries, exhaustion, illness and work animals that collapsed and died at astounding rates. These people were attempting to operate on a rhythm other than the one that was created for them and the results were disastrous.

On the other extreme, there are some cultures that operated on a week of only 3 or 4 days. A person would work two days and then rest one. But the cultural and economic output of such cultures is weaker than those of societies that labor six days before resting one.  

We are not only commanded to rest on the seventh day, but also to work on the first six days. More or less than this and penalties are inevitable.

But Which Day Is the Seventh?

Muslims say Friday is. Jews (and some Christians) say Saturday is. The majority of Christians say Sunday is. Which are right? Or does it matter?

As far as the seven-day Sabbath cycle, it does not matter! Every person tunes his own body to his own personal seven-day cycle – work six days and rest on his own seventh day. Some jobs require Saturday or Sunday work – then, for that worker, his seventh day may be Monday or Thursday. The point is that in every seven-day cycle, there MUST be a day of rest. The functioning of the body requires it, otherwise things become dysfunctional.

What is to be done on the seventh day? God made a very strict keeping of the seventh day in the Old Testament to point out the importance of the day. In the New Testament, those strict requirements have been dissolved along with the whole Old Covenant but the seventh day of rest remains.

The only guidelines given in the New Testament are: 1) rest from work and 2) getting closer to God by church attendance if possible, or time to study God’s Word with prayer.

So, in conclusion, the week was created BY God, to be used in proper bodily function for health, and for recognition of God as Creator and Savior of ALL mankind.