On the Morals of the Catholic Church 12We are United to God by Love, in Subjection to Him.

20. "No other creature," he says, separates us. O man of profound mysteries! He thought it not enough to say, no creature: but he says no other creature; teaching that with which we love God and by which we cleave to God, our mind, namely, and understanding, is itself a creature. Thus the body is another creature; and if the mind is an object of intellectual perception, and is known only by this means, the other creature is all that is an object of sense, which as it were makes itself known through the eyes, or ears, or smell, or taste, or touch, and this must be inferior to what is perceived by the intellect alone. Now, as God also can be known by the worthy, only intellectually, exalted though He is above the intelligent mind as being its Creator and Author, there was danger lest the human mind, from being reckoned among invisible and immaterial things, should be thought to be of the same nature with Him who created it, and so should fall away by pride from Him to whom it should be united by love. For the mind becomes like God, to the extent vouchsafed by its subjection of itself to Him for information and enlightenment. And if it obtains the greatest nearness by that subjection which produces likeness, it must be far removed from Him by that presumption which would make the likeness greater. It is this presumption which leads the mind to refuse obedience to the laws of God, in the desire to be sovereign, as God is.

21. The farther, then, the mind departs from God, not in space, but in affection and lust after things below Him, the more it is filled with folly and wretchedness. So by love it returns to God,--a love which places it not along with God, but under Him. And the more ardor and eagerness there is in this, the happier and more elevated will the mind be, and with God as sole governor it will be in perfect liberty. Hence it must know that it is a creature. It must believe what is the truth,--that its Creator remains ever possessed of the inviolable and immutable nature of truth and wisdom, and must confess, even in view of the errors from which it desires deliverance, that it is liable to folly and falsehood. But then again, it must take care that it be not separated by the love of the other creature, that is, of this visible world, from the love of God Himself, which sanctifies it in order to lasting happiness. No other creature, then,--for we are ourselves a creature,--separates us from the love of God which is in Christ Jesus our Lord.