'Forty Years' in the Bible

Your sons shall be shepherds for forty years in the wilderness, and they will suffer for your unfaithfulness, until your corpses lie in the wilderness.

According to the number of days which you spied out the land, forty days, for every day you shall bear your guilt a year, even forty years, and you will know My opposition.

So the Lord’s anger burned against Israel, and He made them wander in the wilderness forty years, until the entire generation of those who had done evil in the sight of the Lord was destroyed.