This means Jesus is not fully man, with a natural human soul. Mary gives birth to this half-God, who is neither God nor man. This was the solution of Arius, a solution which is very well in line with the hero cult of the ancient world; the world is full of half-gods, of deteriorized gods, of gods who even in Heaven (Olympus) are not fully gods but derived forms of God, and one of them is Jesus – but it is not God Himself.
Now this Christology has been rejected in the first and most important of all Christian councils, that of Nicaea, in June, 325. The text of the decision of Nicaea: “We believe in one God, the Father Almighty, Maker of all things visible and invisible.” – let me stop here for a moment, because all these words are very important. “Invisible” means the Platonic “ideas.” God is the creator not only of the things on earth, but also the creator of the “essences,” as they appear in Plato’s philosophy. “And in one Lord, Jesus Christ, the Son of God, begotten of the Father, the only begotten of the essence of the Father, God of God, and Light of Light, true God of true God, begotten not made, being of one substance (homoousios) with the Father, by Whom all things were made in Heaven and on earth, who for us men and our salvation came down and was incarnate and was made man. He suffered and the third day he rose again, ascended into Heaven. From thence He comes to judge the quickc and the dead.. . and in the Holy Ghost.” Then it goes on to say: “And those who say there was a time when He was not, or He was not before He was made, and He was made out of nothing, and out of another substance or thing, or the Son of God is created or changeable, or alterable: they are condemned by the Holy Catholic and Apostolic Church.”
Now this is the first and fundamental Christian confession. I will give you immediately its significance, but before this a few words of comment: The central phrase is “of one substance with the Father” (homoousios to patri). Then the important thing is that nothing else is said about the Holy Ghost. This was the reason for further struggles and decisions Then the condemnations are interesting: The first and all-embracing one: “Those who say there was a time when He was not … are condemned by the Holy Catholic and Apostolic Church.” Now let me give you, point by point, the significance of this decision for world history and the history of the Church: 1) The main possible Christian heresy was overcome. Christ is not one of the many half-Gods; He is not a hero. He is God Himself appearing in Divine essence within a historical person. – This was the definite negation of paganism. In Arius, paganism again raised its head after it was defeated in the anti-Gnostic struggle, and it raised its head very strongly – Christ, one of the many powers of being – this would have made Christianity one of the many possible religions 2) This fundamental statement was expressed in terms which were more pleasing to Rome and the West than to the East. The East did not like the homoousios; it wanted a ladder of hierarchies. The West, Rome, and her allies in the East, insisted on the homoousios. For this reason the decision of Nicaea was immediately attacked and somehow transformed into something else by the East, in 60 years of struggle and theological work. Only in 381 did this struggle come to an end, and then in terms which pleased the East more than the original formula did, and in new theological interpretations.