Acts 7:23, 30, 36

And when he was full forty years old, it came into his heart to visit his brethren the children of Israel.

And when forty years were expired, there appeared to him in the wilderness of mount Sina an angel of the Lord in a flame of fire in a bush.

He brought them out, after that he had shewed wonders and signs in the land of Egypt, and in the Red sea, and in the wilderness forty years.