It’s a big word, immutability, that simply means that God doesn’t change. There is constancy about him, a steadfast unchangeability that applies to who he is and what he does. One of my favorite passages of scripture is from Hebrews 6, a text that points to a couple of ways in which our God is immutable:
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. (Hebrews 6:17,18 NASB)
God’s purpose, or hiscounsel—the plan he is carrying out in creation—is unchangeable. If God determines that He will do something, then it will certainly be done. We have this text, along with others, that tell us that this is so.
It it is logical, too, that God’s plans are immutable. God’s plans can’t be like my plans, which are subject to change because of unforeseen circumstances, like plumbing disasters, for instance, or even unpredictable feelings like tiredness or crankiness. All of the sorts of things that make my plans subject to change don’t apply to an all-knowing, all-present, all-powerful God.
This text in Hebrews grounds the immutability of God’s counsel in something else—the impossibility of God’s promise changing or his oath being rescinded. His promise and his oath are immutable because it is impossible for God to lie. That God cannot lie points us to the unchanging nature of hischaracter—a character that remains constantly truthful. His promises are certain and he does as he vows, for he has always been truthful, he is always truthful, and he will always be truthful because of his immutable character.
There are many other places in scripture that point to this steadfastness of character that belongs to our God. James 1:13 tells us that God can’t be tempted with evil, nor does he ever tempt anyone with evil. His constant righteousness makes these things impossible for him. Isaiah 40 tells us that God can’t be taught anything, so we know that his knowledge is complete and unchanging. His mercy can be counted on to be enduringly consistent as well, according to Psalm 107:1.
Just as it is logical that God’s counsel is immutable, it is logical that His character is changeless. God is what he is in a complete way—a perfect way. To change would imply increase or decrease, growth or loss, improvement or corruption, and none of these things are compatible with completeness or perfection.
We need to be careful, though, that when we think of God as immutable, we don’t think of him as inactive or completely unfeeling. His character and his plans are unchanging, yet he does not simply sit back to watch those perfect plans unfold. No, he is working constantly within creation to bring his unchanging plans into being. And while it seems certain that God does not feel emotions in exactly the same way we do, we still need to take seriously the statements of scripture that show him manifesting love or joy or anger or wrath. Rather than showing the God is unchangeable, these affections show the unchangeableness of God’s character. He consistently takes pleasure in righteousness, and on the other hand, he is consistently displeased with sin. This constant character assures us that when we change our attitude and actions, his attitude and actions directed toward us are different than they were. That God always loves righteousness and always hates unrighteousness means that the attitudes and actions of God that we experience when we are obedient are different than they are when we sin.
What does it mean for us that our God is immutable? I’d say the biggest benefit to us is that an immutable God is one who can be trusted. His promises are kept with certainty. In the Hebrew 6 passage quoted at the start of this post, it tells us that if we’ve taken our refuge in God, his immutability gives us strong encouragement to hold on to what is promised to us. Because our God is unchanging in both his counsel and his character, the hope we have is an “an anchor of the soul, a hope both sure and steadfast.”
We may think of hope as something elusive, like a rising helium balloon—something that bobs in the wind, dancing away from us just beyond our grasp—but the hope we have in God is not something fleeting. It’s no balloon, but an anchor, because our God is like an anchor. Or a rock. He can be counted on to be forever as he is and to do forever what he says. Out of his steadfast character and standing counsel comes his complete faithfulness.
But this I call to mind,
and therefore I have hope:
The steadfast love of the Lord never ceases;
his mercies never come to an end;
they are new every morning;
great is your faithfulness.
(Lamentations 3:21-23 ESV)