As the eye of the body once put out, can never be restored by the creature's art, so neither can the spiritual eye lost by Adam's sin be restored by the teaching of men or angels. It is one of the diseases which Christ came to cure.
William Gurnall (1979). “The Christian in Complete Armour: A Treatise of the Saints' War Against the Devil: Wherein a Discovery is Made of that Grand Enemy of God and His People, in His Policies, Power, Seat of His Empire, Wickedness, and Chief Design He Hath Against the Saints : a Magazine Opened, from Whence the Christian is Furnished with Spiritual Arms for the Battle, Helped on with His Armour, and Taught the Use of His Weapon: Together with the Happy Issue of the Whole War”, Banner of Truth