Did God Change When He Became Man? Solving the Incarnation Paradox
It is a question that lands in my inbox five or six times a year, and it usually stems from a sincere desire to protect the immutability of God.
The logic of the objection goes like this:
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Premise A: The Bible says God does not change (“For I the Lord do not change” – Malachi 3:6).
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Premise B: The Bible says the Word became flesh (“And the Word became flesh and dwelt among us” – John 1:14).
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The Conflict: If God became something He wasn’t before (a man), doesn’t that imply a change in His very nature? And if He changed, how can He still be God?
The short answer is: No. God did not change. The Incarnation was not a subtraction of deity, nor was it an alteration of the divine essence. To understand why, we have to open the toolbox of historical theology and define one critical term: The Hypostatic Union.
The Essential Tool: The Hypostatic Union
Two thousand years ago, the Second Person of the Trinity (the Son) assumed a human nature. From that microsecond onward, Jesus Christ has subsisted in two natures—one fully divine and one fully human—united in one divine Person.
We must be surgical with our definitions here, just as the Council of Chalcedon was in AD 451:
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Distinct: There is no “mixture” of the natures. Jesus is not a demigod or a hybrid (50% God, 50% man). His divinity remains fully divine; His humanity remains fully human.
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United: Yet, these two natures are not separated like oil and water. They are united in the Hypostasis (the Person) of the Son.
The Logic of Aquinas: Why “Union” Does Not Mean “Change”
But the skeptic asks: “Okay, but isn’t ‘God plus Man’ a change in the equation?”
St. Thomas Aquinas addresses this head-on. He argues that because God is infinite, nothing can essentially be “added” to Him. When the Infinite unites with the finite, the change happens entirely on the side of the finite.
Aquinas writes:
“Since the Divine Person is infinite, nothing can be added to Him… Just as in man’s union with God by grace of adoption nothing is added to God, but what is divine is united to man; and thus God is not perfected, but man.” (Summa Theologiae III, q.3, a.1)
Think of it this way: The change is not in God, but in the human nature that was assumed. Aquinas explains that this relationship is a “created union.” It is real in the creature (the human nature), but it is not “in God” as if it introduced a new moving part into the Divine Being. The assumed humanity now has the Divine Person as its subject, but the Divine Essence remains the Unmoved Mover.
The Verdict: In the Incarnation, God did not change. Rather, human nature was radically exalted. God was not pulled down; humanity was lifted up.
The Root of the Confusion: “Who” vs. “What”
The mistake most people make is failing to distinguish between Person and Nature.
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Person answers the question: “Who is it?”
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Nature answers the question: “What is it?”
In the Incarnation, the “Who” (The Eternal Son) did not change. He is the same yesterday, today, and forever. What happened is that the “Who” took on a second “What” (Human Nature).
The “Who” of Jesus did not change by the addition of an additional “What.” Nor was there any alteration in His original Divine “What.” The only change was the explosive elevation of that specific human nature, which received infinite dignity by being united to the Person of God.
Why This Matters: Worship and Death
This isn’t just word games; it dictates how we worship. Because of the Hypostatic Union, we worship the whole Christ, not just a part of Him.
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We can say God died: Since the person who died on the Cross was the Second Person of the Trinity, we can truly say “God died,” even though the divine nature cannot die. He died according to His human nature.
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We can worship the Man Jesus: We do not commit idolatry when we adore the man Jesus, because that Man is God by personal union.
The Scriptural Witness
This theology isn’t a medieval invention; it is the structure of the New Testament. Look at Colossians 1:15–22.
Paul identifies the “He” (The Person) as the Creator:
“For by Him all things were created… He is before all things, and in Him all things hold together.”
In the very next breath, he identifies the same “He” as the Crucified Man:
“He has now reconciled in His body of flesh by His death.”
It is the same Subject. The same Person. The Creator is the Crucified. The Eternal is the Infant. God became man, and yet God remained God.
