The number 40 has significance throughout the Torah, and the Talmud.
For example, when a person becomes ritually impure, he must go to a ritual bath, a Mikveh. The Talmud tells us that a Mikveh must be filled with 40 measures of water, and a person, must completely submerse himself in it. After being submersed, he leaves the Mikveh ritually pure. It is no accident, that in the story of Noah, the rain poured for 40 days, and surrounded the world with water. And just as a person leaves a Mikveh pure, so too when the waters of the flood subsided, the world was pure.
According to the Maharal (16th century, Prague), the number 40 has the power to raise up something's spiritual state. Just as 40 measures of water purifies a person, and 40 days of rain purified the world, so too Moses being on Mt. Sinai for 40 days also had a purifying effect, in that the Jews arrived at Mt. Sinai as a nation of Egyptian slaves, but after 40 days they were God's nation.
In Deuteronomy, Moses tells the Jewish people that he had "led them 40 years in the wilderness," after he told them that "God has not given you a heart to know, and eyes to see, and ears to hear, until this day." So we see, it took the Jewish people 40 years in the desert before they could understand the things that took place.
And that’s not it. June 3rd will mark the 40th anniversary of Rabbi Sally Priesand’s Ordination from Hebrew Union College as the 1st Woman Rabbi ordained by a Seminary. She has helped open the doors for hundreds of women.