For I the Lord do not change; therefore you, O children of Jacob, are not consumed
Malachi 3:6 ESV
After decades in exile, the LORD brought the people of Judah back to their own land. Upon their return, they rebuilt the altar, began rebuilding the temple, and worshiped their great God who had disciplined them with captivity. But they were not out of the woods just yet. Soon the peoples of the land arose against the people of Judah, harassing them into ceasing the work on God’s temple.
Fifteen years later, the LORD sent His prophets, Haggai and Zechariah, to summon His people into continuing to rebuild the temple. Knowing their fear of opposition, the LORD spoke tenderly to His people, encouraging them to trust His presence and might. Consider one such message:
Yet now be strong, O Zerubbabel, declares the LORD. Be strong, O Joshua, son of Jehozadak, the high priest. Be strong, all you people of the land, declares the LORD. Work, for I am with you, declares the LORD of hosts, according to the covenant that I made with you when you came out of Egypt. My Spirit remains in your midst. Fear not.Haggai 2:4–5
Notice that God spoke to the people of Judah as if He had brought them out of Egypt when, in reality, He did so to their ancestors nearly a thousand years before. Why did the LORD speak to these long-removed descendants of the Exodus as belonging to the same covenant and as being the same people?
ETERNAL GOD, UNCHANGING
The constancy of change is an elemental component of life. We change, as does our environment. In fact, the variation of weather in Oklahoma, my home, gave rise to the slogan: “if you don’t like the weather, just wait five minutes.” The same is true of me. I am a subtly different person than I was five minutes ago, and I am a significantly different person (thankfully) than I was ten and especially twenty years ago. We are ever mutating, constantly becoming different people within a different world.
This is why we find it difficult to grasp statements like the one that God made to the people of Judah. Haggai’s people were many generations removed from their ancestors who were rescued by God from slavery in Egypt. Whole eras passed between those two points of time. Yet God stood with the Judah during Haggai’s day, declaring that His covenant was just as fixed as when He made it with their ancestors a millennia ago.
In many ways, the presence of God at both the Exodus and the return from captivity returns us to God’s eternality. We are born and then die, one generation passing into another. Yet God was before the beginning, with the people of the Exodus and the people after exile, and He will still be at the end of all things. He was, He is, and He is to come. Throughout time and each passing generation, God changes all things “like a robe, and they will pass away, but you are the same, and your years have no end” (Psalm 102:26-27). God’s eternality, therefore, is intimately bound to His immutability.
R. C. Sproul explains that God’s immutability means that “he undergoes no mutations. There is an inner consistency to the nature of God; he never goes through an inward process of evolution.” Fittingly, as with His eternality, the immutability of God is scattered throughout the whole of Scripture. In fact, we can note that Scripture itself is a testament to the unchanging nature of God.
Three of the most explicit texts are as follows. In Numbers 23:19, we read that “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?” Malachi 3:6 also explicitly declares this attribute: “For I the Lord do not change; therefore you, O children of Jacob, are not consumed.” In James 1:17, God is described as “the Father of lights with whom there is no variation or shadow due to change.”
While discussing God’s immutability, we might assume that the biblical writers would focus more upon God’s ontological immutability, that is, His unchangeable being; however, the tendency is instead to proclaim the unchanging purpose of God. For instance, Numbers 23:19 truly referred more to the purposes of God rather than the being of God. Or consider Psalm 33:11: “The counsel of the LORD stands forever, the plans of his heart to all generations.” 1 Samuel 15:29 states, “And also the Glory of Israel will not lie or have regret, for he is not a man, that he should have regret.” Titus 1:2 likewise notes that God cannot lie. Isaiah 46:11 says that “The grass withers, the flower fades, but the word of our God will stand forever.” Psalm 119:160 similarly notes, “The sum of your word is truth, and every one of your righteous rules endures forever.” Jesus Himself noted that heaven and earth would pass away, but God’s law remains fixed and will be accomplished (Matthew 5:18). Furthermore, all of Psalm 136 repeatedly and joyously declares that God’s “steadfast love endures forever.” His love, His Word, and His plans have not changed and will not change; His purpose is eternal as He is eternal. And He cannot lie.
Indeed, it is for our benefit that the Scriptures emphasize the unchanging purpose of God because the immutability of His being necessarily follows. However, if we were told repeatedly that God Himself does not change, we should also naturally believe that His purposes are immutable as well, yet there would likely be much lingering doubt. We might have faith that God is unchanging, but we might still question whether His Word and His love are in flux. Thus, it is for our benefit that God not only assures us that His being does not change but neither does His purpose, His Word, nor His affection for His people.
THE GOD WHO RELENTS?
Yet if God and His plans are immutable, what are we to do with numerous passages of Scripture that seem to indicate that God changes His mind? Is God still truly immutable if He repents of previous declaration?
Consider three of the most notable examples. In Genesis 6:5-6, we are told that “The LORD saw that the wickedness of man was great in the earth, and that every intention of the thoughts of his heart was only evil continually. And the LORD regretted that he had made man on the earth, and it grieved him to his heart.” In Exodus 32, the people of Israel make a golden calf for worship, and the LORD pledges to bring down His wrath upon them. Moses, however, intercedes for the people, “and the LORD relented from the disaster that he had spoken of bringing on his people” (v. 14). Finally, in the book of Jonah, God issued a decree of judgment upon Nineveh (a message which contained no call for repentance), and yet the Ninevites did repent before the LORD. We are then told that “when God saw what they did, how they turned from their evil way, God relented of the disaster that he said he would do to them, and he did not do it” (3:10).
Each of these examples seems to involve God being caught by surprise and in some form appearing to change His mind. But can this be true?
Jeremiah 18:5-11 provides a very clear answer to this seemingly grand dilemma:
Then the word of the LORD came to me: “O house of Israel, can I not do with you as this potter has done? declares the LORD. Behold, like the clay in the potter’s hand, so are you in my hand, O house of Israel. If at any time I declare concerning a nation or a kingdom, that I will pluck up and break down and destroy it, and if that nation, concerning which I have spoken, turns from its evil, I will relent of the disaster that I intended to do to it. And if at any time I declare concerning a nation or a kingdom that I will build and plant it, and if it does evil in my sight, not listening to my voice, then I will relent of the good that I had intended to do to it. Now, therefore, say to the men of Judah and the inhabitants of Jerusalem: ‘Thus says the LORD, Behold, I am shaping disaster against you and devising a plan against you. Return, every one from his evil way, and amend your ways and your deeds.’
In other words, God happily relents of His judgments whenever sinners repent. As the LORD said twice to Ezekiel, He takes no “pleasure in the death of the wicked” (18:23; 33:11). Indeed, His dispositional will is “that all should reach repentance” (2 Peter 3:9). He is slow to wrath for our sake. He is patient and merciful toward us, giving us time and time again to turn in repentance toward Him. As God spoke to Moses as He passed by him, He is “merciful and gracious, slow to anger, and abounding in steadfast love and faithfulness, keeping steadfast love for thousands, forgiving iniquity and transgression and sin, but who will by no means clear the guilty, visiting iniquity of the fathers on the children and the children’s children, to the third and fourth generations” (Exodus 34:6-7).
Notice that both are held in tandem. The LORD will not clear the guilty, but He also forgives sin by His steadfast love, mercy, and grace. How can these both be true? The answer is only found in Jesus Christ, the Son of God.
Due to the immutability of God’s goodness, righteousness, justice, and holiness, He cannot simply pass by sin as if it did not exist. That is not how forgiveness works, even though that is often the assumption. Instead, God’s eternal and unchanging justice demands restitution for sin’s trespass, and because sin is against the infinite and eternal God, sin’s consequences are both infinite and eternal as well. Eternal torment, therefore, is only proper penalty for our rebellion.
Yet God, by His boundless love for us, made another way. The eternal Word, the second person of the triune God, united Himself to humanity and lived a life entirely without sin. He then willingly submitted Himself to death in our place. Because He was still entirely God, the death of Jesus Christ was a death of eternal and infinite proportions. His single, physical death paid the penalty for all our sins, once for all. Thus, God’s justice is maintained. Sin is still punished, eternally so. Yet God is also able to grant forgiveness, full forgiveness, a forgiveness that declares to us that no condemnation exists for we who are in Christ Jesus (Romans 8:1).
The work of Jesus, therefore, also maintains the immutability of God, while also allowing us to change, to repent of our sin. Indeed, this plan of redemption was God’s “eternal purpose that he has realized in Christ Jesus our Lord” (Ephesians 3:11). Our sin was no surprise to Him, and neither was His plan to rescue us by the blood of His Son. Ransoming His people from the slavery of sin was His purpose during the Exodus, during the return from captivity, during the crucifixion of our Lord, today, and in eternity past before time ever began. Just as He Himself cannot change, His redeeming love for His people is also immutable.
 Sproul, Enjoying God, 113.