The creed reads: He is one, certainly not by the blending of his essence, but by the unity of his person.
That which made the Son of God, the Son of God, did not change during the incarnation. We saw that much in the previous statement, and through the words of Paul in Philippians 2. Instead of the Son of God being changed by becoming a human being, he took upon himself humanity and, thus, remained as he was and always had been: the Son of God from all eternity.
This truth leaves us with the wonderfully complex and mystifying reality that Jesus Christ, is one within himself while being God and man. There is no hint of a complex unity of persons like there is within the godhead (see Genesis 1:26: then God said, “Let us make man in our image.”).
There is not a fractured existence with Jesus where his divinity and humanity are fighting it out with one another. As we saw before, Jesus is truly and completely God while, through his incarnation, being truly and completely man.
In the one person of Jesus—the Son of God—there is unity. There is unity between the natures of Jesus, just like there is unity among the persons within the Trinity. It is impossible to speak of the biblical God without assuming the existence of the Trinity. In a similar manner, following the incarnation, it is impossible to speak of the existence of Jesus without assuming the reality of his divinity and humanity.
To put it another way: God is complex, therefore, the Son of God is complex. However, his complexity is not a barrier to keep us from him; instead, it’s an invitation to come and see, and worship this Jesus.