'Forty Years' in the Bible

Then for forty years the land had peace, till the death of Othniel, the son of Kenaz.

So may destruction come on all your haters, O Lord; but let your lovers be like the sun going out in his strength. And for forty years the land had peace.

So Midian was broken before the children of Israel and the Midianites never got back their strength. And the land had peace for forty years, in the days of Gideon.

And the children of Israel again did evil in the eyes of the Lord; and the Lord gave them into the hands of the Philistines for forty years.