God’s Immutability and the Incarnation: Irreconcilable Differences?

How can we say that God is immutable or unchangeable, and yet say that God took on a human nature that is subject to change?

When we say God is immutable, we are speaking of his divine nature, which is incapable of any internal change. “Changeableness” would imply the capacity for an increase or decrease of perfection, which would necessarily imply limitation and imperfection. As God, Jesus is necessarily infinitely perfect and thus not subject to internal change. Otherwise, he necessarily wouldn’t be God. For more on God’s immutability, see this article which discusses that and other divine attributes.

At the same time, in taking on a human nature, which given its human limitations could be perfected (Heb. 2:10-11; 5:7-10), Jesus illustrates that he can experience changes relative to his humanity and yet not as a divine person. A mystery to be sure, but here we speak of “mystery” as a divine truth that we humanly cannot fully comprehend, nor will be able to fully comprehend, given God’s divine majesty.