The active immutability of God, the ever-living and eternally unchanging interpenetration of the divine persons, translates into the divine willingness, without a shadow of turning, to make us partakers of that gloriously inalterable and living incorruptibility. We are most fortunate that in the incarnation God is not engaged in a work of self-realization but in the redemptive working-out of his eternal glory: incarnation is, in its immutable purpose, God with us and for us. Such doctrine, I would hope, will never be viewed as “subevangelical.” Our piety must not falter before the first paradox, the involvement of immutable God, because on the first rest the second, the transformation of death into life, of corruptibility into incorruptibility.
Richard A. Muller, “Incarnation, Immutability, and the Case for Classical Theism, Westminster Theological Journal, 45 (1983), 40.
Richard Muller is here responding to an essay by Clark Pinnock, “The Need for a Scriptural, and therefore Neo-Classical Theism.” Pinnock’s argument is that the traditional conception of God as immutability, atemporal, and so forth are pagan philosophical imports.
For many Bible-believing Christians there is a ring of truth to Pinnock’s statements. The God of systematic theology can appear a cold and distance deity. He may, especially when the vocabulary is unfamiliar, poorly defined, and not applied to worship seem dead.
Further, the proponents of the mutability of God almost always rely on first-sight readings and common sense arguments. 1 Samuel 15:35, “And the LORD regretted that He had made Saul king over Israel.” The Son of God was not Jesus of Nazareth in 5 BC and he became the Jesus in 3AD, therefore the Son of God changes. It certainly sounds like God changes.
But the issue as Muller and to a lesser degree Pinnock points out is:
The issue concerns the logical and theological priority of one set of statements over another. Do we read statements concerning divine repentance as dependent for their meaning upon logically prior statements concerning the absence of change in God, or ought we to read statements concerning the absence of change in God, or ought we to read statements concerning the divine constancy as meaningful only when qualified by a doctrine of actual divine repentance? (31)
To put it into terms of our life experience: the husband who says he loves his faithful wife as he is divorcing her to marry a younger woman is lying. And we know this because behind the statement “I love you,” are prior actions that define and explain the meaning and purpose of the words.
In terms of theology, Christians must draw “ontological and essential conclusions from texts which speak of the ethical, moral, intentional, and volitional constancy of God.” These “ontological and essential conclusions” require a vocabulary that relies on Scripture but is not found in Scripture. And they must be tested by their reasonableness within a scriptural framework. Theological construction and canonical interpretation (the word “became” in John 1:14 is defined by canon’s conception of God and not the immediate context alone) are necessary.
We must do this because for God to be the person he describes himself to be he must be immutable. Or as Muller summarizes, “A God who repents as human beings repent not only falls short of immutability, he also falls short of omniscience” (33).
The entire point of the Muller’s closing paragraph, which begins this essay, is that the only God that can save us is an immutable, Trinitarian, incarnate Son, indwelling Spirit, and instigating Father. If God is not those things, then there is no salvation, and “our faith is futile and you are still in your sins. Then those also who have fallen asleep in Christ have perished” (1Co 15:17-18).
As Paul says in 1 Corinthians 15:20, “But in fact,” the God of the Bible is unchangeable, eternal, omnipresence, one, spiritual, self-existent, all knowing, invisible, wise, truthful, good, loving, timeless, beautiful, and blessed. And so we are saved.