Q. You said God never change. Then how can Jesus become a man forever after the incarnation? Isn’t that change?
A. The immutability of God is an attribute where “God is unchanging in his character, will, and covenant promises.” This is based on a number of Scriptures:
• Num 23:19 God is not a man, that He should lie, Nor a son of man, that He should repent; Has He said, and will He not do it? Or has He spoken, and will He not make it good?
•1 Sam 15:29 Also the Glory of Israel will not lie or change His mind; for He is not a man that He should change His mind.”
• Ps 102:26 Even they will perish, but You endure; …
• Mal 3:6 For I, the LORD, do not change; …
• Heb 6:17-18 In the same way God, desiring even more to show to the heirs of the promise the unchangeableness of His purpose, interposed with an oath, so that by two unchangeable things in which it is impossible for God to lie, we who have taken refuge would have strong encouragement to take hold of the hope set before us.
• Jas 1:17 Every good thing given and every perfect gift is from above, coming down from the Father of lights, with whom there is no variation or shifting shadow.
Notice that all the passages refer to God’s character, will, and promise. Immutability does not mean that God is static and therefore never changes. God is dynamic, but always acts according to His nature. He won’t act contrary to His character.
What about Jesus? In the incarnation, God the Son took on human nature and became man. The Council of Chalcedon (AD 451) declared that in Christ there are two natures, deity and humanity, each retaining its own properties, and together united in one subsistence and in one single person (hypostatic union). The Word was unchanged as He entered a union with sinless human nature in a physical body:
• Col 2:9 For in Him all the fullness of Deity dwells in bodily form,
God the Son did not change His divine nature at the incarnation. His deity did not mix or blend with His humanity, which would necessitate change. Instead, His deity resides in His humanity in the Person of Christ.
With respect to His divine nature, Jesus as God is immutable or unchanging:
• 2 Tim 2:13 If we are faithless, He remains faithful, for He cannot deny Himself.
• Heb 1:12 … But you remain the same, and your years will never end.
• Heb 13:8 Jesus Christ is the same yesterday and today and forever.
Nothing of His character, will and promise changed as a result of the incarnation.
With respect to His human nature, Jesus as man is mutable or subject to change:
• Lk 2:40 The Child continued to grow and become strong, increasing in wisdom; …
• Jn 4:6 … So Jesus, being wearied from His journey, was sitting thus by the well. …
• Lk 22:44 And being in agony He was praying very fervently; and His sweat became like drops of blood, falling down upon the ground.
He could grow, get tired, suffer, and die.
One question remains. How did this union happen? I don’t know, because the Bible didn’t explain. All I can say is that God chose not to reveal to us, perhaps because we do not have the capacity to understand it. It is a mystery, but not a contradiction. It is easier to understand if the two natures blend together to form a hybrid, but that’s not what the Bible taught. Just as the Trinity is a mystery, so is the incarnation. I can go only as far as the Bible reveals it, the rest is hidden from us, which I accept by faith.