[Moses decides to lead Israel out of Egypt.]
“When Moses was forty years old, he decided to visit his fellow Israelites.”
– Acts 7:23 

[After living 40 years on the backside of the desert in the land of Midian.]
“After forty years had passed, an angel appeared to Moses in the flames of a burning bush in the desert near Mount Sinai” – Acts 7:36 

[Beginning of Moses' speech after leading Israel in the desert for 40 years]
“The LORD your God has blessed you in all the work of your hands. He has watched over your journey through this vast desert. These forty years the LORD your God has been with you, and you have not lacked anything.”
– Deuteronomy 2:7

[Ending of Moses' speech after leading Israel in the desert for 40 years]
“Then Moses went out and spoke these words to all Israel: I am now a hundred and twenty years old and I am no longer able to lead you. The LORD has said to me, ‘You shall not cross the Jordan.’”
– Deuteronomy 31:2

“and Isaac was forty years old when he married Rebekah daughter of Bethuel the Aramean from Paddan Aram and sister of Laban the Aramean.”
– Genesis 25:20

“So the land had peace for forty years, until Othniel son of Kenaz
[ Caleb’s younger brother ] died.”
– Judges 3:11

[ The ending of the Song of Deborah ]
“’So may all your enemies perish,
O LORD! But may they who love you be like the sun when it rises in its strength.’
Then the land had peace forty years.”
– Judges 5:31

[ Gideon’s Death ]
“Thus Midian was subdued before the Israelites and did not raise its head again. During Gideon’s lifetime, the land enjoyed peace forty years.”
– Judges 8:28

[ The Birth of Samson ]
“Again the Israelites did evil in the eyes of the LORD, so the LORD delivered them into the hands of the Philistines for forty years.”
– Judges 13:1

“When he mentioned the ark of God, Eli fell backward off his chair by the side of the gate. His neck was broken and he died, for he was an old man and heavy. He had led Israel forty years.”
– 1 Samuel 4:18

“David was thirty years old when he became king, and he reigned forty years.”
– 2 Samuel 5:3

“Solomon reigned in Jerusalem over all Israel forty years.”
– 1 Kings 11:41

[ Joash Repairs the Temple ]
“Joash was seven years old when he became king, and he reigned in Jerusalem forty years. His mother’s name was Zibiah; she was from Beersheba.”
– 2 Chronicles 24:1

“No foot of man or animal will pass through it; no one will live there for forty years.”
– Ezekiel 29:10