[Watchingtheweasels]

The Orthodox Church holds a memorial for those who have reposed in Christ on the 40th day.

Moses, Elijah, and Jesus fasted for 40 days.

Jonah preached to Nineveh for 40 days.

Moses was on Mt Sinai for 40 days.

Ezekiel laid on his side for 40 days.

Goliath taunted Israel for 40 days.

God made the flood last 40 days.

Then there are the 40 years in the wilderness.

Anyone know the origin of the significance of the number 40?

 

[OhioMan]

Found this....hope this helps, I'm sure there is more on "40"

The number 40 has great significance throughout the Torah and the Talmud. The number 40 represents transition or change; the concept of renewal; a new beginning. The number 40 has the power to lift a spiritual state. Consider:
When a person becomes ritually impure, he must immerse in a ritual bath, a mikveh. The Talmud tells us that a mikveh must be filled with 40 se'ahs (a measure of water). Immersion in a mikveh is the consummate Jewish symbol of spiritual renewal.
It is no accident that in the story of Noah, the rain poured for 40 days, and submerged the world in water. Just as a person leaves a mikveh pure, so too when the waters of the flood subsided, the world was purified from the licentiousness which had corrupted it in the days of Noah.
Moses was on Mt. Sinai for 40 days and came down with the stone tablets. The Jews arrived at Mt. Sinai as a nation of Egyptian slaves.

 

[ActionJackson]

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Question: "What is the significance of ‘40 days’ in the Bible?"

Answer: The number 40 shows up often in the Bible. Because 40 appears so often in contexts dealing with judgment or testing, many scholars understand it to be the number of “probation” or “trial.” This doesn’t mean that 40 is entirely symbolic; it still has a literal meaning in Scripture. “Forty days” means “forty days,” but it does seem that God has chosen this number to help emphasize times of trouble and hardship.

I like this site and use it often: [url]https://www.gotquestions.org/40-days-Bible.html

 

[ActionJackson]

Here's another interesting take:

The Meaning of Numbers: The Number 40

Mentioning 146 times in Scripture, the number 40 generally symbolizes a period of testing, trial or probation. During Moses' life he lived forty years in Egypt and forty years in the desert before God selected him to lead his people out of slavery.
Moses was also on Mount Sinai for 40 days and nights, on two separate occasions (Exodus 24:18, 34:1 - 28), receiving God's laws. He also sent spies, for forty days, to investigate the land God promised the Israelites as an inheritance (Numbers 13:25, 14:34).
The prophet Jonah powerfully warned ancient Nineveh, for forty days, that its destruction would come because of its many sins. The prophet Ezekiel laid on His right side for 40 days to symbolize Judah's sins (Ezekiel 4:6).

https://www.biblestudy.org/bibleref/meaning-of-numbers-in-bible/40.html

 

[Watchingtheweasels]

...I suspect that this is one of those questions that we won’t get a definitive answer to in this life...