What do we mean when we say God doesn’t change? In Scripture we see God appealing to His unchanging nature:
For I the Lord do not change; therefore you, O children of Jacob, are not consumed. (Malachi 3:6)
Every good gift and every perfect gift is from above, coming down from the Father of lights with whom there is no variation or shadow due to change. (James 1:17)
Jesus Christ is the same yesterday and today and forever. (Hebrews 13:8)
This is where we get the doctrine of immutability. According to Wayne Grudem in his book, Bible Doctrine, this doctrine means that “God is unchanging in his being, perfections, purposes, and promises . . . ” In the past, people have misunderstood this aspect of God to mean that He doesn’t change in any way at all. He’s a static being who isn’t subject to the slightest alteration, whether intrinsic or extrinsic.
In ancient Greek philosophy, the monistic philosophers spoke of a universal oneness that is completely unchanging because it is eternal, infinite, and perfect. Aristotle spoke of the “Unmoved Mover”, a being that caused all motion, but itself didn’t move. Since this thing or being is eternal, infinite, and perfect, it can’t change, because all change, according to them, is either for the better or for the worse. If it gets better, it wasn’t already perfect; if it gets worse, then it loses its essential attribute of perfection. Some theologians, who believed God is eternal and perfect, adopt this view of God and said that He is Himself completely unchanging in every respect. If God could change, it would be either for the better or for the worse, and that goes against Scripture.
However, it also goes against Scripture to say that God doesn’t change in any way at all, which is why many Christian thinkers today reject the radical immutability of the Greek philosophers and early theologians. Grudem finishes off his definition of immutability by saying “. . . yet God does act and feel emotions, and he acts and feels differently in response to different situations.” This is why Scripture can show God being wrathful in response to one situation (Exodus 32:10) and merciful in response to another situation (Jonah 3:10). In Philosophical Foundations for a Christian Worldview, William Lane Craig and J.P. Moreland make the point that not all change makes something better or worse. Some change is simply neutral. “A perfect being need not change ‘vertically,’ so to speak, on the scale of perfection . . . but could change ‘horizontally,’ remaining equally perfect in both states.” For example, right now God may change from knowing that it’s 4:00 PM to knowing that it’s 4:01 PM. This is a change, but it’s not a change for the worse. If God is a perfect being who knows all truths, we would expect Him to always know the right time!
Instead, God is completely unchanging in His eternity, His being, His perfections, His purposes, and His promises. The God who justly destroyed Sodom and Gomorrah and mercifully spared Nineveh, the God who kept His promises to Abraham, Isaac, and Jacob, and the God who sent His Son to save sinners two thousand years ago is still the same God today.
So what can we take away from this? The changing aspects of God means that He is a dynamic, living being who experiences us personally and who we can experience as well. He’s not frozen into emotionless immobility, but responds to us with joy at our salvation and grieving at our rejection of Him. God’s unchanging nature means that we can always trust Him and put our hope in Him. He’ll never change the good plans He made for those who love Him and He’ll never act arbitrarily towards us. He is our Rock and Fortress (Psalm 18:2), and anyone who puts their hope in Him has stable foundations in this world and the next (Matthew 7:24-25).