The second partof the Summa Theologica of the “Universal Doctor,” Thomas Aquinas, begins with the following sentence: Because man has been created in God's image, now after having spoken of God, the archetype, we must still deal with His image which is man. (Summa Theologica I, II, Prologus.) There is something peculiar about this sentence; its meaning must not be misunderstood. It is stated as a matter of fact but its meaning is not to be taken for granted. This first sentence of Moral Theology expresses a fact which has almost entirely disappeared from the knowledge of Christians of today; namely, die fact that moral doctrine is primarily and above all a doctrine about man; that moral doctrine must plainly reveal the conception of man, and that, therefore, the doctrine of Christian morals must concern the Christian model of man. This fact was a matter of course in' the Christianity of the high Middle Ages. This fundamental conception—which, to be sure, was not definitely taken for granted as the polemical wording shows—compelled Eckhart to say two generations after St. Thomas: people should not think about what they ought to do, they should rather think about what they ought to be.