This truth about God is worthy of all wonder and adoration. It focuses, indeed, it fixates our praise on One who is entirely unchanging in his praiseworthiness. At no point ought we to expect that God will “let us down” or do something not in keeping with his perfect goodness and wisdom. As the Dutch theologian Herman Bavinck put it, “Those who predicate any change whatsoever to God, whether with respect to his essence, knowledge, or will, diminish all his attributes: independence, simplicity, eternity, omniscience, and omnipotence. This robs God of his divine nature, and religion of its firm foundation and assured comfort.” He’s right! There’s real comfort in knowing our God is not fickle, flakey, or faddish. No, our God has unchangeably determined the end from the beginning.
A favorite hymn we sing at church is Walter Smith’s “Immortal, Invisible, God Only Wise” where the congregation beautifully confesses that “We blossom and flourish as leaves on a tree, and wither and perish, but naught changeth Thee.” My heart soars in adoration as we sing that last clause, “but not changeth Thee.” What is being expressed here is the glorious doctrine of God’s immutability, the belief that God cannot and does not change. To be sure, this doctrine, along with its close sister impassibility, has grown entirely out of favor with many modern thinkers and even some self-proclaimed evangelicals. But to deny either is neither safe nor right and will inevitably reduce God the Creator to that of a mere creature.
Indeed, all creatures – every person, every animal, all existence created by God – has within its essence the unavoidable characteristic of potentiality. Creatures change because there is always the potential for change. Being, as we are, finite creatures, we are all limited to time and space and are therefore always gripped with inescapable potential. We have the potential to grow, to change positions within a room, or to have the future become our present. Everything finite is limited by the potential of what can or could be, and every creature is finite. But not so with God.
God, being as he is, an Infinite being is free within himself of any and all potential. Classical theologians have referred to God as Pure Actuality; He is Pure Act. Though he has the power to effect change in others, helping his creation reach their potential and their own finite perfection, He himself has no potential because He already is Perfection. Consider that glorious truth! God never undergoes change since He is infinite in his perfections. If God is not a God who is becoming (how could he since he’s eternal; his infinite nature transcends time itself), and he is therefore always the same, well then, he is not a God who has potential. God does not change.