- days and nights it rained while Noah was on the ark
- years Israelites lived on Manna in the desert
- days & nights Moses was on the mountaintop with God
- days & nights Moses was with God a second time
- years Moses was in the wilderness before returning to Egypt
- x 2, Moses' age at the Exodus (80)
- x3, Moses' age at his death (120)
- days the 12 spies searched the land of Canaan
- years Israel wandered in the desert.
- stripes comprising the maximum whipping penalty in Mosaic law (Deuteronomy 25:3)
- years God allowed the land to rest (Judges 3:11)
- years of another period of rest for the land
- years of still another period of rest for the land.
- sons of Abdon (a judge in Israel)
- years of an enemy given to Israel in punishment for evil-doing (Judges 13:1)
- years Eli judged Israel
- days Goliath taunted Israel
- years Saul reigned
- age of Saul's son when he began to reign
- years of David's rule
- cubit length of the holy place of the temple
- baths (measurement) of temple lavers
- sockets of silver per grouping in the Temple
- years of Solomon's reign
- days Elijah received strength from one meal
- days & nights Elijah walked to mountain of the Lord
- days Ezekiel bore the iniquity of the house of Judah
- years of Jehoash's rule
- years Egypt to be laid desolate
- cubit length of Ezekiel's symbolic temple
- cubit length of courts of Ezekiel's temple
- days Nineveh given to repent
- days and nights Jesus fasted (Mt. 4:2)
- days Jesus was tempted (Luke 4:2, Mark 1:13).
- days Jesus remained on earth after resurrection
Seems to have something to do with a time of testing followed by fulfillment of God's promises. Talmudic understanding of the number's significance here. Here's B16, from his new book:
In Jesus' day the number 40 was already filled with rich symbolism for Israel. First of all, it recalls Israel's 40 years' wandering in the desert, a period in which the people were both tempted and enjoyed a special closeness to God....
Just so you know.