Because we are limited we cannot grasp all of God’s nature, so we think of him in different ways and he reveals himself with different names. These perfections are not multiple in God, however: since he is simple, they are one in and with his essence. God is not lacking in any perfection or power: since he moves the creation towards their perfections, he must first have every perfection. He does not have a body, since bodies are not simple, and one must first move the body to move something else. Since he cannot be a member of a species, there is only one God. God is not a species or genus he is uniquely existence. His essence is himself, since he cannot have accidental properties as a simple being-his essence is his existence. He must also be a simple being, without composite parts. All of God’s existence is eternal and without succession. He is a necessary being, since he cannot change or come into existence he depends on nothing outside of himself. Movement requires explanation, and there cannot be an infinite series of movers. The fact that God exists is known by reason. It is through Christ’s humanity that we come to know the deity. The knowledge of faith turns on knowing the Trinity, as well as the humanity of Christ. Faith, hope, and love are required for living, and they work together. Our salvation consists in knowing the truth of God.

The infinite Word of God added smallness to himself and came to earth to save us. The Second Treatise on Faith: The Humanity of Christ The First Treatise on Faith: The Divine Trinity Written to be accessible, this book is an introduction to Aquinas’s thought which presents his basic theology without reproducing all of his subtle philosophical argumentation. Although he never finished it (the text breaks off where he died), his treatises on Faith and Christ provide a rather full synopsis of his doctrine.

Near the end of his life, Aquinas was asked to produce a concise version of his massive and intricate Summa Theologica. A Brief Book Summary from Books At a Glance

A shorter summa