We call ungodly anyone who is without the Spirit of God, for Scripture says it is to justify the ungodly that the Spirit is given. But when Christ distinguishes the Spirit from the flesh by saying: “That which is born of the flesh is flesh,” and adds that what is born of the flesh cannot see the Kingdom of God [John 3:6, 3], it plainly follows that whatever is flesh is ungodly and under the wrath of God and a stranger to the Kingdom of God. And if it is a stranger to the Kingdom and Spirit of God, it necessarily follows that it is under the kingdom and spirit of Satan, since there is no middle kingdom between the Kingdom of God and the kingdom of Satan, which are mutually and perpetually in conflict with each other. These are the facts which prove that the loftiest virtues of the heathen, the best things in the philosophers, the most excellent things in men, which in the eyes of the world certainly appear to be, as they are said to be, honorable and good, are nonetheless in the sight of God truly flesh and subservient to the kingdom of Satan; that is to say, they are impious and sacrilegious and on all counts bad.
The Bondage of the Will
Luther’s Works Vol. 33