Fundies should appreciate this. It's been 40 years since Martin Luther King, Jr, was shot & killed.
Because of 40 days / 40 nights of the Flood and 40 years wandering in the desert while the generation that refused to enter into the promised land all died off, 40 has come to symbolize a "period of cleansing" as well as one generation. (Jesus' fasting in the desert for 40 days and 40 nights is a fulfillment of of what the Israelites in the desert could not do - remain true to God and trust in His providing.) Later in the book of Judges, the people had peace off and on for periods of roughly 40 years. (The people would rebel against God and worship false god's. When they started experiencing difficulty, they cried out to God who delivered them. Afterward, they would have peace for about 40 years until the until the next generation -- which had not seen God's deliverance -- went back to the idols.)
Here are the references to the number '40' in the bible:
There are three things that are stressed during the 40 days of Lent: prayer, fasting, and almsgiving. Forty (40) from the list below is symbolic for trial, testing, and waiting. But in the use of the number 40 there is one underlying focus: it is a journey (see Pope Benedict XVI’s comments below), even if physical, it always leads to a spiritual time of growth and change.
It rained 40 days and 40 nights during the Flood (Genesis 7: 4)
Noah waited 40 days after the waters receded and the Ark settled on Mount Ararat before he sent out the raven (Genesis 8: 3-8)
Isaac was 40 years old when he married Rebecca (Genesis 25: 20)
Esau was 40 years old when he married his two wives (Genesis 26: 34)
The Israelites ate Manna 40 years in the Desert (Genesis 16: 35-6)
Moses spent 40 days and nights on Mount Sinai (Exodus 24: 18) comes down to the Golden Calf, break the tables. Then in Exodus 24: 28 he returns and fasts 40 days and 40 nights.
The scouts from the 12 tribes spied out the Promised Land 40 days before they returned a bad report (Numbers 13: 25)
Therefore, the Israelites were required to spend 40 years “wandering” in the Wilderness (Numbers 14: 33; Deuteronomy 29: 4)
Joshua was 40 years old when he spied with the scouts (Numbers 13: 5; Joshua 14: 7)
Goliath “taunted” Israel 40 days before his defeat by David (1 Samuel 17: 16)
King David reigned for 40 years (2 Samuel 5: 4)
King Solomon reigned for 40 years (1 Kings 11: 42)
Jonah preacah3ed to Nineveh for 40 days before they repented (Jonah 3: 4)
Elijah fasted 40 days in the wilderness (1 Kings 19: 8)
Purification of Mary is 40 days after birth of Jesus (Leviticus 12: 1-4) (Luke 2: 22-4)
Jesus spent 40 days Fasting in the Desert after His baptism (Matthew 4: 1-2)
Jesus also spent 40 days on earth following His Resurrection (Acts 1: 3)
Jesus, by tradition, spent 40 hours in the tomb.
http://www.divinemercysundayusa.com/Divine%20Mercy%20and%20The%20Biblical%20Significance%20of%2040%20Days.docPerhaps the cleansing of America really does begin tomorrow. Someone should probably give James Dobson a heads-up.