'Forty Years' in the Bible

For the children of Israel walked forty years in the wilderness, till all the people that were men of war who came out of Egypt were consumed, because they obeyed not the voice of the LORD: to whom the LORD swore that he would not show them the land which the LORD swore to their fathers that he would give us, a land that floweth with milk and honey.

Forty years old was I when Moses the servant of the LORD sent me from Kadesh-barnea to explore the land; and I brought him word again as it was in my heart.