“God is not man, that he should lie, or a son of man, that he should change his mind. Has he said, and will he not do it? Or has he spoken, and will he not fulfill it?”
(Numbers 23:19 ESV)
We are surrounded by constant change, at an ever-increasing pace. Jobs change. Children grow. Our favorite business closes down. People we thought we knew will do something completely unexpected. Health declines. Loved ones leave us.
In the midst of all this change, it is comforting to know that God is our rock. He never changes. Theologians call this divine attribute immutability. God is eternally the same, and that is a solid comfort for us.
Because God is perfect, he can’t change for the better, and he will not change for the worse. He never has an “off ” day. He always was and always will be all that he is. He is always perfectly just, holy, and loving—never more nor less than who he is. What a comfort this is when we are disappointed by the changeability of our fellow humans. Peoples’ love may wane, they may behave differently toward us based on circumstances or emotions, but God never does. He is always faithful, even when we are faithless (2 Timothy 2:13).
God’s decrees—what he wills—are also unchanging. He says, “I am God, and there is none like me, declaring the end from the beginning and from ancient times things not yet done, saying, ‘My counsel shall stand, and I will accomplish all my purpose’” (Isaiah 46:9-10). If God has promised something, it is as good as done. That is why the Bible sometimes speaks of our sanctification and glorification in the past tense (Romans 8:30). We may not have it fully yet, but because it depends on God, it is a sure thing. He always does what he says he will do.
The immutability of God is inextricably connected to his omniscience. We change our minds based on new information. But God already knows it all; nothing is a surprise to him. Therefore, he has already planned and foreknown everything that happens, so he does not need to change in order to respond to our needs.
Sometimes people struggle to reconcile God’s immutability with his response to prayer. God seems to change his mind based on the prayers of the faithful (Genesis 18:22-33; Exodus 32:14). In these cases, human agency is part of the process through which God works his eternal intentions. He responds to us in relationship, but he already knows what we will do. Indeed, it is the utter reliability of this unchanging God that draws us into prayer. We know he loves us and will listen to us because he is the eternal, immutable God.