The number forty is used by God to represent a period of testing or judgment (the length of time necessary to accomplish some major part of Gods plan in his dealings with various portions of mankind). The 40 days of rain in the days of the flood were the judgments of God. The 40 day periods of fasting, testing, and communing with God that were faced by Moses and Jesus were a form of God's judgments. The forty years that the Israelites spent in the wilderness were also the judgments of God. Various leaders in Israel who reigned for 40 year periods were put there BY God according to His Will and Judgments. Egypt was left desolate for 40 years because of God's judgments.