In Sacred Scripture, the number forty is a sign of penance:
* God made it rain for forty days and forty nights in the days of Noah (Gen 7:4 - by the way they only ate fish on the ark, not meat)
* Moses spent forty days fasting on Mount Sinai with God (Exodus 24:18)
* The People of Israel people wandered forty years traveling to the Promised Land (Numbers 14:33)
* Elijah spent forty days and forty nights walking to Mount Horeb (1 Kings 19:8)
* Jonah prophesied forty days of judgment for Nineveh to repent (Jonah 3:4).
* Jesus fasted for forty days days in the wilderness, and was tempted by the devil (Matthew 4:1-2, Mark 1:12-13, Luke 4:1-2)
* Jesus was also in the tomb for about forty hours.