On the Morals of the Catholic Church

²² Let this same Paul tell us who is this Christ Jesus our Lord. "To them that are called," he says, "we preach Christ the virtue of God, and the wisdom of God." And does not Christ Himself say, "I am the truth?" If, then, we ask what it is to live well—that is, to strive after happiness by living well—it must assuredly be to love virtue, to love wisdom, to love truth, and to love with all the heart, with all the soul, and with all the mind; virtue which is inviolable and immutable, wisdom which never gives place to folly, truth which knows no change or variation from its uniform character. Through this the Father Himself is seen; for it is said, "No man comes unto the Father but by me." To this we cleave by sanctification. For when sanctified we burn with full and perfect love, which is the only security for our not turning away from God, and for our being conformed to Him rather than to this world; for "He has predestinated us," says the same apostle, "that we should be conformed to the image of His Son."

23. It is through love, then, that we become conformed to God; and by this conformation, and configuration, and circumcision from this world we are not confounded with the things which are properly subject to us. And this is done by the Holy Spirit. "For hope," he says, "does not confound us; for the love of God is shed abroad in our hearts by the Holy Spirit, which is given unto us." But we could not possibly be restored to perfection by the Holy Spirit, unless He Himself continued always perfect and immutable. And this plainly could not be unless He were of the nature and of the very substance of God, who alone is always possessed of immutability and invariableness. "The creature," it is affirmed, not by me but by Paul, "has been made subject to vanity." And what is subject to vanity is unable to separate us from vanity, and to unite us to the truth. But the Holy Spirit does this for us. He is therefore no creature. For whatever is, must be either God or the creature.