And the Word became flesh and dwelt among us, and we beheld his glory, glory as of the Only-Begotten from the Father, full of grace and truth.
(John 1: 14)
Although he existed in the form of God, he did not consider equality with God something to be grasped, but he emptied himself by taking the form of a servant and being made in human likeness.
(Phil. 2: 6-7)
These two biblical texts proclaim what is at once both the central truth of the Christian faith and perhaps its most controversial affirmation. God has become a man. The one who was equal with God has taken upon himself the form of a servant. In the man Jesus who has lived among us, we see the glory of the Father's only Son. As early as ad 325, this affirmation was enshrined prominently in the Creed of Nicaea, even though the Council of Nicaea dealt not with the incarnation per se, but with the full deity of God the Son. The Creed affirms not only that 'we believe in one God, Father all-sovereign, maker of all things seen and unseen; and in one Lord Jesus Christ, the Son of God', but also that this Son of God 'for us men, and for our salvation, came down, and was incarnated, and was made man, suffered, and arose on the third day'.
The prominence given to the incarnation in the Creed of Nicaea set in motion a series of intense theological discussions that led to serious controversies about christology. These controversies were eventually resolved (to some degree) at the Council of Chalcedon in ad 451, whose Definition of Faith determined the language which the vast majority of the Christian