Why Seven Days? (Beshalach)

“Time is the most valuable coin in your life. You and you alone will determine how that coin will be spent. Be careful that you don’t let other people spend it for you.” — John Dryden

A seven-day week does not reflect any natural phenomenon. Unlike a day, a lunar month, or a solar year, the week is an entirely human construct.

There have been notable alternatives. The Igbo people of Nigeria traditionally used a four-day week. In Indonesia, the Javanese observed a five-day cycle, while the Akan peoples of West Africa followed a six-day week—later combined with a seven-day system to create a forty-two-day cycle.

History offers even more experiments. The Romans once used an eight-day week, until the seven-day cycle gained wider acceptance. Ancient China and Egypt both employed ten-day weeks. In the fervor of revolution, the French adopted a ten-day week as well, a system that lasted nine and a half years (1793–1802). The Soviet Union experimented with a five-day week from 1929 to 1931, followed by a six-day week until 1940. None of these systems endured.

So why does nearly all of humanity follow a seven-day week?

Ibn Ezra (on Exodus 16:1) explains that it originates in the Torah. God established a seven-day cycle both to commemorate Creation and to remember the Exodus. It is striking that the entire world has adopted this Jewish framework—often without any awareness of its source.

It makes one wonder: what other Jewish ideas have quietly shaped the world, and which ones might yet do so?

Shabbat Shalom,

Ben-Tzion

Dedication

To the return of the body of Ran Gvili, z”l, our last hostage in Gaza.