The Hardening and the Firstborn Text: Exodus 4:18-23
Introduction: The Logic of Divine Sovereignty
We come now to a pivotal moment in the life of Moses, and by extension, in the life of Israel and the world. Moses, having received his commission from the burning bush, now has to act on it. And in this short passage, we are given a master class in the way God operates in the world. Modern evangelicals, particularly those of the more squeamish varieties, often want a God who is a sort of divine gentleman, one who would never impose His will on anyone. They want a God who makes suggestions, not decrees. But that is not the God of the Bible. The God of Scripture is an absolute sovereign, and nowhere is this sovereignty more starkly, and for some, more uncomfortably, on display than in the Exodus narrative.
This passage deals with two monumental themes that are inextricably linked: the absolute sovereignty of God in salvation and judgment, and the covenantal principle of federal headship, represented by the firstborn. These are not abstract theological categories for seminarians to debate. These are the very hinges upon which redemptive history turns. God is about to go to war with the gods of Egypt, and He is laying out the terms of engagement for His field commander, Moses. And the central issue is this: who is in charge? Is Pharaoh the ultimate power in Egypt? Is man the master of his own fate? Or is Yahweh the king over all the earth, who does as He pleases in heaven and on earth, who raises up kings and brings them down, and who hardens one man's heart in order to save His people?
What we will see is that God's plan is comprehensive. He does not simply react to Pharaoh's stubbornness; He ordains it. He does not just respond to events; He authors them. This is difficult for our modern, democratic sensibilities, which assume that the ultimate value is individual autonomy. But the Bible teaches that the ultimate value is the glory of God. And God has determined to get glory for His name through both the salvation of His people and the just destruction of His enemies. This passage is the divine declaration of war, and the terms are unconditional surrender.
The Text
Then Moses went and returned to Jethro his father-in-law and said to him, "Please, let me go, that I may return to my brothers who are in Egypt and see if they are still alive." And Jethro said to Moses, "Go in peace."
And Yahweh said to Moses in Midian, "Go, return to Egypt, for all the men who were seeking your life are dead."
So Moses took his wife and his sons and mounted them on a donkey and returned to the land of Egypt. Moses also took the staff of God in his hand.
And Yahweh said to Moses, "When you go to return to Egypt, see to it that all the miraculous wonders which I have put in your hand, that you do them before Pharaoh; but as for Me, I will harden his heart with strength so that he will not let the people go.
Then you shall say to Pharaoh, 'Thus says Yahweh, "Israel is My son, My firstborn.
So I said to you, 'Let My son go that he may serve Me'; but you have refused to let him go. Behold, I will kill your son, your firstborn."'"
(Exodus 4:18-23 LSB)
Obedience and Providence (vv. 18-20)
We begin with Moses' departure from Midian.
"Then Moses went and returned to Jethro his father-in-law and said to him, 'Please, let me go, that I may return to my brothers who are in Egypt and see if they are still alive.' And Jethro said to Moses, 'Go in peace.' And Yahweh said to Moses in Midian, 'Go, return to Egypt, for all the men who were seeking your life are dead.' So Moses took his wife and his sons and mounted them on a donkey and returned to the land of Egypt. Moses also took the staff of God in his hand." (Exodus 4:18-20)
Moses, after his encounter with God, begins to obey. His first step is an act of courtesy and respect. He asks permission from his father-in-law, Jethro. This is not incidental. Moses is not a wild-eyed revolutionary; he is a man operating within the established structures of authority. He honors his earthly obligations even as he is about to undertake a divine commission. True faith does not make a man a boor. He gives a partial explanation, which is both true and prudent. He doesn't need to give Jethro the full download of the burning bush incident. He simply says he wants to check on his kinsmen, and Jethro blesses him.
Then God gives Moses a crucial piece of providential encouragement. "All the men who were seeking your life are dead." Forty years prior, Moses fled Egypt as a wanted man, a murderer. Now God clears the way. This is a tender mercy from a sovereign God. God does not always remove all obstacles, but He often removes the ones that we think are insurmountable. Moses' greatest fear, the reason he fled, has been taken care of by the simple passage of time, orchestrated by a sovereign God. God's timing is perfect. He did not call Moses a moment too soon or a moment too late.
So Moses sets out. He takes his wife, Zipporah, and his two sons, Gershom and Eliezer. This is a family affair. The deliverance of God's covenant people is to be undertaken by a man leading his own covenant family. This is the biblical pattern. And notice what he takes with him: "the staff of God." This is the same shepherd's crook from the previous chapter, the ordinary stick that God had consecrated for an extraordinary purpose. It was a simple piece of wood, but in Moses' hand, it was the instrument of divine power. It represents the authority of God delegated to His servant. God loves to use ordinary, humble means to accomplish His mighty purposes, so that no flesh may glory in His presence.
The Divine Hardening (v. 21)
Now we get to the theological heart of the matter. God gives Moses his final briefing before he enters Egypt.
"And Yahweh said to Moses, 'When you go to return to Egypt, see to it that all the miraculous wonders which I have put in your hand, that you do them before Pharaoh; but as for Me, I will harden his heart with strength so that he will not let the people go.'" (Exodus 4:21 LSB)
This verse is a stumbling block for many, but it is a cornerstone of a robust doctrine of God's sovereignty. God tells Moses to perform the signs, but then He says that He, God, will be the one to ensure they don't work, at least not initially. God is not just predicting Pharaoh's resistance; He is ordaining it. The Hebrew word for "harden" here is chazaq, which means to strengthen, to make firm, to fortify. God is going to fortify Pharaoh's heart in its native rebellion.
Does this mean Pharaoh is not responsible? Not at all. The Bible is perfectly comfortable holding two truths in tension: God is absolutely sovereign, and man is fully responsible for his sin. Throughout the plague narrative, the text will say both that Pharaoh hardened his own heart and that God hardened Pharaoh's heart. These are not contradictory; they are two sides of the same coin. Pharaoh, in his pride and idolatry, is already inclined to resist God. His heart is a stone. God, in His sovereignty, does not merely "permit" this; He strengthens Pharaoh's resolve. He gives Pharaoh's sinful volition a divine backbone. He ensures that Pharaoh's rebellion will not collapse prematurely under the pressure of the plagues.
Why would God do this? The Apostle Paul gives us the definitive answer, quoting this very story in Romans 9. "For the Scripture says to Pharaoh, 'For this very purpose I have raised you up, that I might show my power in you, and that my name might be proclaimed in all the earth.' So then he has mercy on whomever he wills, and he hardens whomever he wills" (Romans 9:17-18). God's purpose in hardening Pharaoh's heart was not primarily about Pharaoh. It was about displaying the full spectrum of His power and glory to Israel, to Egypt, and to the surrounding nations. He was setting the stage for a demonstration of His justice and His salvation so magnificent that it would be remembered for all time. A quick and easy deliverance would not have accomplished this. God wanted a full-scale war to demonstrate His complete supremacy over every false god Egypt trusted in.
The Firstborn Principle (vv. 22-23)
God then gives Moses the central message, the declaration that frames the entire conflict.
"Then you shall say to Pharaoh, 'Thus says Yahweh, "Israel is My son, My firstborn. So I said to you, 'Let My son go that he may serve Me'; but you have refused to let him go. Behold, I will kill your son, your firstborn."'" (Exodus 4:22-23 LSB)
This is the principle of covenantal, corporate headship. God declares that the entire nation of Israel is, corporately, His "firstborn son." In the ancient world, the firstborn son held a position of special honor, privilege, and inheritance. He was the principal heir and the representative of the father. By calling Israel His firstborn, God is declaring His unique, covenantal love for them and their preeminent status among the nations. They are His treasured possession. This is a direct challenge to Pharaoh, who was considered the son of Ra, the sun god. God is saying, "You think you are a son of a god? I am the true God, and this nation of slaves is My son."
The purpose of this sonship is service, or more accurately, worship. "Let My son go that he may serve Me." The conflict is fundamentally a liturgical one. Who will Israel worship? Will they continue to build treasure cities for Pharaoh, serving the gods of Egypt? Or will they be set free to worship Yahweh, their true Father and King? There is no neutral ground. You will either serve God or you will serve a pharaoh of some kind.
And here God lays out the ultimate sanction, the lex talionis, the law of just retribution. The conflict is framed from the very beginning as a battle over the firstborn. "You have refused to let My firstborn son go. Therefore, I will kill your firstborn son." This is not a petty threat. It is a declaration of divine justice. The final plague is not an arbitrary act of cruelty; it is the perfectly just and symmetrical response to Pharaoh's crime. Pharaoh's sin is a capital offense against God's own Son. By enslaving and oppressing Israel, Pharaoh is attacking God's chosen heir. The punishment will therefore fall on Pharaoh's heir.
Conclusion: The Greater Firstborn
This entire narrative is a shadow, a type, pointing forward to a greater reality. The story of Exodus is the gospel in miniature. We, like Israel, are born into slavery, in bondage to the tyranny of sin and death. The pharaoh of this world, Satan, holds us captive, and we are forced to build his kingdom. Our hearts, like Pharaoh's, are naturally hard, rebellious, and set against God.
But God has a Firstborn Son, a greater Son than Israel. His name is Jesus Christ, the only begotten of the Father. And the Father sent His Son into the domain of darkness on a rescue mission. He came to the tyrant and said, "Let My people go, that they may serve Me." And just as Pharaoh's heart was hardened, the rulers of this age, instigated by the prince of darkness, hardened their hearts against Jesus. They refused to let Him go.
But in a glorious and terrible irony, God's justice against the oppressor was executed upon His own Son. On the cross, God did to His own Firstborn what He had threatened to do to Pharaoh's firstborn. He struck Him down. Jesus Christ, the true and better Israel, endured the ultimate plague, the curse of God's wrath against sin, on our behalf. He was slain so that the angel of death would pass over us.
And through His death and resurrection, He has accomplished the true Exodus. He has plundered the kingdom of darkness and set the captives free. God hardens the hearts of those who persist in rebellion, like Pharaoh, so that His power might be displayed in their just judgment. But He softens the hearts of His elect, cracking the stone and giving us a heart of flesh, so that His grace might be displayed in our salvation. The message to us is the same as it was to Pharaoh: let go of your rebellion. Bow the knee to God's true Firstborn, the Lord Jesus Christ. For if you refuse to let God's Son rule over you, you will face a judgment far more terrible than the death of the firstborn in Egypt.