How Did the Son’s Incarnation Impact the Trinity?

The doctrines of the incarnation (Jesus Christ as God in human flesh) and the Trinity (one God in three persons) are two of historic Christianity’s most distinctive teachings. In fact, these two doctrinal truths separate the historic Christian faith from the two other major Middle Eastern monotheistic religions of Judaism and Islam.1

Yet these biblically revealed doctrines contain great mystery, for God is infinite and eternal while human beings—in stark contrast—are finite, temporal creatures. Nevertheless, the Christian church in its historic councils and creeds through the centuries has taken great care to define and offer models of explanation concerning these doctrinal truths.2

Recently, a Facebook friend asked me a series of questions about how Jesus’s state as the incarnate Son of God related to the broader Christian conception of God as Trinity. I’ve included our exchange here (paraphrased) and hope you’ll find it helpful in your theological reflection.

Questions on the Trinity
I want to better understand the relationship between Jesus Christ’s incarnation and the other persons of the Trinity. For example, what happened to the “nature of the Triune Godhead” while the Son (Jesus Christ) was finite here on Earth, but the Father and Holy Spirit were not confined to a finite body? How can one member be finite but the others are not? Can one member have a separate and seemingly distinct, temporal existence, while the other two do not share in that, or so it seems? 

My other questions are related. What happened to the “nature of the Trinity” while Christ was temporal but God the Father and the Holy Spirit were, at least before creation, timeless? The same goes with omniscience. How is Christ limited in his understanding but the other two members of the Godhead are simultaneously all-knowing? 

It seems, from a layman’s perspective, that there is a fundamental change occurring between the three of them. I hope you can help me to understand this better.

My Response
The general Christian orthodox view is that while Jesus Christ was a single person with two distinct-yet-united natures (deity and humanity), during his incarnation the divine nature continued to act in all ways consistent with the Godhead (infinite, eternal [or timeless], omniscient, etc.). So there was no change to the Son’s divine nature (or attributes) that he shares fully and equally with the Father and the Spirit and thus no change in the ontological nature of the Trinity. In the incarnation, the Son simply took to himself a human nature and thus became the God-man.

Jesus’s limitations in his earthly ministry reflected only his human nature. The person of Christ was the eternal Son but it appears Christ usually operated in his human nature and sometimes through his divine nature. A possible analogy is that Christ’s two levels of awareness (human and divine) operated similarly to the human conscious and subconscious states. His human nature would reflect Christ’s conscious awareness while the divine would reflect his subconscious awareness (deeper and yet always available). 

The two natures in Christ’s incarnation are united in the one person but do not mix or mingle and therefore do not negate or deny one another. So the human nature is not divinized and the divine nature is not dragged down. Thus, having two natures is not a logical contradiction because there is no negation or denial (no A and non-A). Yet there is still great mystery in the incarnation.3 

Thanks for these great theological questions. Keep studying historic Christian doctrine.

Reflections: Your Turn
Why are the doctrines of the incarnation and the Trinity so important to Christianity? Visit Reflections on WordPress to comment.



  1. Traditional Jews and Muslims deny both the incarnation and the Trinity and instead affirm a unitarian view of God (a single God who is one in being and one in person and thus has no begotten coequal son to be incarnated).
  2. For a detailed biblical, theological, and apologetics discussion of the incarnation and the Trinity, see Kenneth Richard Samples, Without a Doubt: Answering the 20 Toughest Faith Questions (Grand Rapids, MI: Baker Books, 2004), chapters 5 (Trinity) and 9 (incarnation).
  3. For a detailed discussion of how the incarnation relates to the Trinity in terms of mystery and logic, see Christianity Cross-Examined: Is It Rational, Relevant, and Good? (Covina, CA: RTB Press, 2021), chapter 5.