Forty days appears 25 times in Scripture.
Of course the first reference is to Noah and the flood:
Genesis 7:4 For yet seven days, and I will cause it to rain upon the earth forty days and forty nights; and every living substance that I have made will I destroy from off the face of the earth.
Genesis 7:12 And the rain was upon the earth forty days and forty nights.
Genesis 7:17 And the flood was forty days upon the earth; and the waters increased, and bare up the ark, and it was lift up above the earth.
Note: It rained 40 days and nights the water pevailed for 150 days but Noah was on the Ark for 1 year.
Genesis 8:6 And it came to pass at the end of forty days, that Noah opened the window of the ark which he had made:
The next reference in regarding the length of time for embalming a body. Genesis 50:3 And forty days were fulfilled for him; for so are fulfilled the days of those which are embalmed: and the Egyptians mourned for him …
Moses is called by God into the top of Mt Sinai.
Exodus 24:18 And Moses went into the midst of the cloud, and gat him up into the mount: and Moses was in the mount forty days and forty nights.
Moses is called by God unto the top of Mt Sinai a second time, tablets of stone.
Exodus 34:28 And he was there with the LORD forty days and forty nights; he did neither eat bread, nor drink water. And he wrote upon the tables the words of the covenant, the ten commandments.
12 men spying out the land. (see 12 Spies)
Numbers 13:25 And they returned from searching of the land after forty days.
Numbers 14:34 After the number of the days in which ye searched the land, even forty days, each day for a year, shall ye bear your iniquities, even forty years, and ye shall know my breach of promise.
Moses recounts receiving the tablets (10 commandments) of stone. Deuteronomy 9:9 When I was gone up into the mount to receive the tables of stone, even the tables of the covenant which the LORD made with you, then I abode in the mount forty days and forty nights, I neither did eat bread nor drink water:
Deuteronomy 9:11 And it came to pass at the end of forty days and forty nights, that the LORD gave me the two tables of stone, even the tables of the covenant.
Deuteronomy 9:18 And I fell down before the LORD, as at the first, forty days and forty nights: I did neither eat bread, nor drink water, because of all your sins which ye sinned, in doing wickedly in the sight of the LORD, to provoke him to anger.
Deuteronomy 9:25 Thus I fell down before the LORD forty days and forty nights, as I fell down at the first; because the LORD had said he would destroy you.
Deuteronomy 10:10 And I stayed in the mount, according to the first time, forty days and forty nights; and the LORD hearkened unto me at that time also, and the LORD would not destroy thee.
Goliath challenges Israel:
1 Samuel 17:16 And the Philistine drew near morning and evening, and presented himself forty days.
Elijah, when dealing with Ahab and Jezebel: note: Horeb is Siani
1 Kings 19:8 And he arose, and did eat and drink, and went in the strength of that meat forty days and forty nights unto Horeb the mount of God.
Ezekiel and the siege against Israel (a sign):
Ezekiel 4:6 And when thou hast accomplished them, lie again on thy right side, and thou shalt bear the iniquity of the house of Judah forty days: I have appointed thee each day for a year.
Nineveh had 40 days to repent and turn to God:
Jonah 3:4 And Jonah began to enter into the city a day’s journey, and he cried, and said, Yet forty days, and Nineveh shall be overthrown.
At the beginning of his ministry, the Lord Jesus fasted:
Matthew 4:2 And when he had fasted forty days and forty nights, he was afterward an hungred.
Mark 1:13 And he was there in the wilderness forty days, tempted of Satan; and was with the wild beasts; and the angels ministered unto him.
Luke 4:2 Being forty days tempted of the devil. And in those days he did eat nothing: and when they were ended, he afterward hungered.
The Lord walked on earth to prove he had indeed risen from the Grave.
Acts 1:3 To whom also he shewed himself alive after his passion by many infallible proofs, being seen of them forty days, and speaking of the things pertaining to the kingdom of God
To better understand, read the verses in context.
