How can Jesus be the Son of God, but be the same person?

I assume you’re asking here how Jesus can be both divine and human. Well, that has been the question ever since the resurrection and before. A great old Jesuit theology professor ours, Brian Daley, S.J., once said the Mystery of the Trinity is “Three Whos in One What.” The Mystery of the Incarnation is “Two whats in One Who.”

Richard McBrien’s magisterial Catholicism roots the Christian understanding of God in the reality of the Trinity. But we could not know the Trinity without Jesus having come and “lived [literally ‘tabernacled’] among us” (John 1:14).

O’Brien goes on to say we are interested in Jesus because Jesus saves us. And, “If he is not truly God, then he could not SAVE us. If he is not truly a human being, he could not save US. If divinity and humanity are not united in a single person, then HE could not save us (O’Brien, 1981, P. 371. Study Edition. Emphasis in the original).

It took the church several hundred years to come to the definitive articulation of Jesus Christ as True God and True human at the Council of Nicea in 325 (That’s from where we get the Nicene Creed we recite every Sunday at Mass). Councils of Constantinople (381), Ephesus (431), Chalcedon (451) and Constantinople II (553) further codified what we mean when we say Jesus is both human and divine.

There’s another old saying in theology. All you can say about Jesus is that he’s God and human. As soon as you say anything else, you begin to emphasize the divinity or the humanity and are thus tending towards heresy.