Numbers 13:25
At the end of forty days they returned from spying out the land.
Exodus 24:18
Moses entered the cloud and went up on the mountain. And Moses was on the mountain forty days and forty nights.
Exodus 34:28
So he was there with the LORD forty days and forty nights. He neither ate bread nor drank water. And he wrote on the tablets the words of the covenant, the Ten Commandments.
Numbers 14:33-34
And your children shall be shepherds in the wilderness forty years and shall suffer for your faithlessness, until the last of your dead bodies lies in the wilderness.