Nestorius was ready to grant that the union between the Word and human nature was as high and intimate as possible, so far as moral union can permit; but never would he concede that it was any higher than simple moral union, which kept whole and entire the two individualities united. Consequently, he admitted two persons and two individualities in Christ—the Word of God, and the man called Christ. From which theory it follows that our Lord was a mere man—a saint, if you will, the highest of all saints, yet simply a man.
Catholic doctrine, on the contrary, teaching that the union of the Word and the human nature was personal, inasmuch as the divine person of the Word was the subsistence in which his human nature subsisted, teaches consequently, at the same time, that in Christ there is one person, one individuality—the divine personality of the Word; that therefore Christ, the new individual, is God, being the second divine person, in which both his divine and human nature subsist. Nor was the human nature of this new individual so absorbed by the divine personality as to cease to be a substance, as Eutyches affirmed, who upheld, it would seem, a fusion and a mixture of the two natures altogether inconceivable and absurd.
From all we have said we may form quite an accurate idea of what the hypostatic union really means. It is the union, or the meeting, so to speak, of the human and divine natures in the one single point of contact, the infinite personality of the Word of God; the human nature having no personality of its own, but subsisting of the identical personality of the Word.
The new individual possessed of the divine and human nature in the unity of the single personality of the Word is Jesus Christ.
To complete now the idea of the hypostatic union, we shall point out some consequences which evidently flow from that union:
1. We should consider that nature being transmitted through generation, and Christ being possessed of two natures, the human and the divine, it is necessary to admit in him a twofold generation: one eternal, according to which he received the divine nature from the Father; the second temporal, by which he received his human nature from the Virgin Mother.
2. As nature is the radical principle and source of operation in every being, it follows that, as Christ is possessed of two natures, we must predicate of him a double operation—one human, the other divine.
3. In force of the same principle, we must predicate of him whatever necessarily belongs to the two distinct natures. Hence, as intelligence and will, together with their respective perfections, belong both to the human and to the divine nature, it is clear that we must attribute to Christ, first, a divine intelligence and a divine will with their perfections, such as infinite wisdom and knowledge, infinite holiness, goodness, justice, etc.; second, a human intelligence and a human will, together with the perfections of these faculties, as knowledge, wisdom, holiness, etc.
4. As actions, though immediately proceeding from nature, are to be attributed to the subsistence and personality, because nature could not act without being possessed of subsistence, and as the subsistence and personality of both natures of Christ is one—the personality of the Word of God; and as this personality is infinite, it follows that the actions of Christ, whether immediately springing from his human nature, or proceeding from his divine nature, have all an infinite worth and excellence, on the ground of the infinite worth of the person to whom they must be attributed. This principle, so evident, and grounded on the axiom of ideology to which we have alluded—Actiones sunt suppositorum—has been denied by some, especially Unitarians. But happily the most abstract principles of ideology have such a bearing upon human dignity that it is easy to refute such would-be philosophers on the strong ground of the dignity of the human species. Let us give an instance. How are the actions immediately proceeding from the corporal nature of man, such, for instance, as those of locomotion, distinguished from the actions of locomotion in the brutes? And why is it that the actions of locomotion of the first may attain the highest and most heroic moral worth, while the same actions in the brute may never have a moral dignity? Ontologically they are the same. An animal may move its foot; I may do the same; both movements may save the life of a man. In me, the stirring of my foot may have the dignity of a moral and heroic action. In the brute, it can never have it. What causes the difference? The difference lies in the fact that I am a person, the brute is not. I, being a person, the supreme, first, and independent principle of action of both my natures, corporal and spiritual, it follows that all actions radically flowing from either of my natures are to be attributed to me as person, as the supreme and independent principle of them; and as I, as a person, am capable of moral dignity, all the actions, whether proceeding from my corporal or my spiritual nature, become capable of moral worth and dignity.
In Christ, the personality or the supreme and independent principle of action of both his natures, human and divine, being one, it is evident that whether his actions radically proceed from his human nature, or spring from his divine nature, they must all be attributed to his one and single person; and as the person is infinite, the worth and dignity of all his actions is simply infinite. As in man the personality of both corporal and spiritual natures being capable of morality, the action springing from either nature may have a moral dignity and worth. We shall conclude this article by answering a few objections raised by Unitarians against the hypostatic union. We shall take them verbatim from Dr. Channing's lecture on Unitarian Christianity: