For 40 days and 40 nights the rain fell upon the earth.

So what?

The Torah tells us that the Almighty opened the “well-springs of the deep,” from which most of the water came forth to inudate the world.  And Rashi calculates that the water remained upon the earth for exactly one solar year.  If so, of what significance is it that the rain fell for 40 days and nights?

The number 40 appears in Jewish tradition with curious frequency.  Moses ascended Sinai and remained there for 40 days and nights, not once but twice to receive each set of tablets.  According to the commentaries, he ascended one additional time in between, also for 40 days and nights, to petition HaShem to forgive the Jewish people for the sin of the golden calf.

The Jews wandered in the desert for 40 years, and the spies sent to investigate the land traveled its length and breadth for a period of 40 days.  It is also taught that one should study Talmud until the age of 40 before engaging in the study of kabbalistic teachings.  Our greatest kings, David and Solomon, each ruled for 40 years, as did the greatest of our judges, Deborah.

What is the significance of the number 40, and how does it relate to the Great Flood?

The Talmud tells us that the neshoma, or soul, enters an embryo 40 days after conception.  Until then (although life has certainly begun), the incipient baby is a soulless golem, an arrangement of organic matter that can barely be called a human being.  On the fortieth day, the insertion of the soul transforms this lump of developing flesh into the world’s most extraordinary creation:  a future Man, fashioned b’tzelem Elokim, in the image of G-d.

It would appear, therefore, that the number 40 signifies not physical birth but spiritual birth, the process through which homo sapiens becomes human, a populace becomes a nation, a leader brings his people to a new level, and a scholar acquires the spiritual maturity to begin investigating the mystical secrets of the universe.

In the same way, the 40 days and nights of rain may have signified the process through which the Almighty restored the spiritual equilibrium of the world, suspending one complete cycle of creation for a full calendar year, immersing the earth in the purifying mikveh waters of the Flood.  And, just like the waters of any kosher mikveh must originate with a volume of 40 sa’ah of naturally flowing water, so too did the Flood require an accumulation of rainwater over a period of 40 days.

With the corruption of the first ten generations of man washed away, human beings could return to their ultimate task of perfecting the world, physically diminished but with renewed spiritual potential.  And the persistant sign of the Flood — the rainbow  — reminds us that such potential remains with us even until today, every moment of our lives.