The number forty appears many times in the Bible:
- Forty days and nights of rain during the flood
- Moses lived forty years in Egypt
- Moses spent forty days on Mount Sinai
- The Jews journeyed through the desert for forty years to the Promised Land
- Jonah preached forty days to Nineveh
- The prophet Ezekiel laid on his right side for forty days to symbolize the sins of Judah
- Elijah fasted for forty days on Mount Horeb
- Goliath taunted Israel for forty days
- Jesus fasted in the desert forty days
Generally speaking, the number forty has been considered to be used in the Bible as a rounded number. It was used to express a complete period of time rather than expressions like “many” or “some.” It would be similar to referring to a number of years ranging from eight to twelve as “about a decade.” In this case, the number forty is being used instead of saying “a few days” or “a few decades.”
Its use denotes a complete period of time that transitions to another period of time. After each forty days or years listed above, a great event occurs, or a definitive transition takes place. It’s a more effective and dramatic literary device than saying, “After some time [momentous moment] began.” It also helps the sacred author highlight theological parallels.
When we see the number forty used to denote time in the Bible, we are being told that something extraordinary and definitive is happening.