Summa summae S. Thomae sive compendium theologiae

[ That man was made to the image of God is plainly established from Holy Scripture. Genes., I, 26, God says: Let us make man to our image and likeness. And it is added, ibid., 27: And God created man to his own image: to the image of God he created him: male and female he created them. The same is said in Sap., II, 23 and Eccli., XVII, 1. But the question is in what respect man is the image of God.

I say: Man is a true image of God by reason of his intellectual nature, imperfect, however¹.

Proof of the first part. Two things are required for the note of an image. First, that it be like that of which it is the image in the specific note and ultimate difference, or in the mark of the species, or at least in the noblest property thereof. Second, that the likeness be expressed and derived from that of which it is called the image, because a thing is called an image from the fact that it imitates another: thus a son is the image of his father, the representation of Caesar in copper is the image of Caesar, because each is in the likeness of the specific nature or its mark, and expressed and derived from that of which it is the image. But man has these two conditions with respect to God, by reason of his intellectual nature. Therefore. — Proof of the minor. Man is expressed and made by God himself according to the likeness of that intellectual nature which in God is the ultimate difference and, as it were, the species; for according to this intellectual nature, man is apt to know and love God, just as God knows and loves himself. Therefore.

Proof of the second part². The likeness of God in man is not unto equality, since the exemplar exceeds it infinitely. And Holy Scripture indicates this, saying that man was made to the image of God; for the preposition to signifies a certain approach which befits a thing that is distant. Hence the Son of God alone is the perfect image of the eternal Father; because, (made) if he himself is the image of God, as the Apostle testifies, II Cor., IV, 4, he was not made, but begotten to the image of God, as his natural and consubstantial Son.

Although the image of God is found in every individual of human nature, whether male or female, yet according to something secondary the man displays the image of God relative to the woman, and not conversely. For as God is the principle and end of every creature, so the man is the principle and end of the woman. Hence, when the Apostle had said, I Cor., XI, 7, that the man is the image and glory of God, but the woman is the glory of the man, he gives the reason, adding, ibid., 8 and 9: For the man is not of the woman, but the woman of the man, namely as to their first creation, and: For the man was not created for the woman, but the woman for the man.

You will ask whether in man there is the image of God, not only as regards the divine nature, but also as regards the trinity of persons.

I answer affirmatively³. Man not only imitates the divine nature insofar as he understands and loves himself, but also insofar as, by understanding himself, he produces the Word, and by loving himself, Love. For man likewise, by knowing God, produces a word, and by loving him produces love; and thus in him is found the principle of the word, the word, and love, by which in God the trinity of persons is constituted. But because understanding and loving are not necessary operations in man, they are not substantial in him, nor do they constitute persons, and in this respect too, although man is a true image of God, he is nevertheless an imperfect image.]