The Self-Devouring Fire Text: Isaiah 9:18-21
Introduction: Sin's Bonfire
We live in a sentimental age, an age that has tried to domesticate God. We want a God who is a celestial therapist, a divine affirmation machine, one who would never be so rude as to get angry. Our generation has exchanged the consuming fire of Sinai for a decorative scented candle from the mall. But the God of Scripture is not safe, and He is certainly not tame. The prophet Isaiah will not allow us to entertain such comforting delusions. He shows us that sin has consequences, and those consequences are not arbitrary penalties tacked on by a peevish deity. The consequences are baked into the very nature of the sin itself. Sin is its own judgment. It is a fire that, once kindled, consumes everything in its path, including, eventually, the arsonist.
In this passage, Isaiah is continuing a series of pronouncements against the northern kingdom of Israel. This is the third of four stanzas of judgment, each one concluding with the same terrible refrain: "In spite of all this, His anger does not turn back, and His hand is still stretched out." This is not the hand of mercy, but the hand of judgment. It is the hand of a God who has given His people over to the very thing they desired. They wanted to be their own gods, to live by their own rules, to kindle their own fires. And God, in His wrath, says, "Very well. Live in the inferno you have built."
What Isaiah describes here is a society coming apart at the seams. It is a picture of total social disintegration. And the engine of this collapse is wickedness. We tend to think of sin as a private affair, a series of discrete, individual choices. But Isaiah shows us that sin is corporate. It is a contagion. It is a wildfire that leaps from person to person, from family to family, from tribe to tribe, until the entire forest of the nation is ablaze. This is not just a description of ancient Israel; it is a diagnosis of any society that rejects the Lordship of Christ. When a people abandons God, they do not find liberation; they find that they have set themselves on fire.
The Text
For wickedness burns like a fire; It consumes briars and thorns; It even sets the thickets of the forest aflame, And they roll upward in a column of smoke. By the fury of Yahweh of hosts the land is burned up, And the people are like fuel for the fire; No man spares his brother. They slice off what is on the right hand but still are hungry, And they eat what is on the left hand but they are not satisfied; Each of them eats the flesh of his own arm. Manasseh devours Ephraim, and Ephraim Manasseh, And together they are against Judah. In spite of all this, His anger does not turn back, And His hand is still stretched out.
(Isaiah 9:18-21 LSB)
Wickedness as Wildfire (v. 18)
The prophet begins with a powerful simile, explaining the physics of societal collapse.
"For wickedness burns like a fire; It consumes briars and thorns; It even sets the thickets of the forest aflame, And they roll upward in a column of smoke." (Isaiah 9:18)
Wickedness is not a static state; it is an active, energetic, consuming force. It has a life of its own. It is a fire. Notice the progression. It starts by consuming the "briars and thorns." This refers to the common people, the rabble, the underbrush of society. Sin often finds its first fuel among the undisciplined and foolish. But it does not stop there. A fire that is not checked will not be content with the kindling. It "even sets the thickets of the forest aflame." It moves from the undergrowth to the great trees, the leaders, the established institutions, the very structures that make a society what it is. No one is safe.
The result is a column of smoke that rolls upward. This is a picture of a nation's glory, its substance, its very life, dissipating into nothing. All their grand plans, their political machinations, their cultural achievements, all of it goes up in smoke. This is what happens when a nation’s foundational wickedness is left to burn. It is not that God stands far off and zaps them with lightning bolts. It is that He removes His restraining grace and allows the natural consequences of their sin to run their course. He lets the fire they started do what fire does.
The Fury of God and the Fuel of Man (v. 19)
Isaiah immediately clarifies that this natural process is also a supernatural judgment. The fire of sin is stoked by the fury of God.
"By the fury of Yahweh of hosts the land is burned up, And the people are like fuel for the fire; No man spares his brother." (Isaiah 9:19 LSB)
The fire of wickedness is not an autonomous force operating outside of God's sovereignty. It is the very instrument of His wrath. "By the fury of Yahweh of hosts the land is burned up." God's fury is not like our petty, sinful anger. It is the settled, holy, righteous opposition of His character to all that is evil. When a people persistently chooses sin, they place themselves in the path of this holy fury, and the result is combustion.
And what is the fuel for this fire? "The people are like fuel for the fire." This is a terrifying image. The very people who started the fire become its sustenance. Sin is cannibalistic. It feeds on the sinner. When a society turns from God, it turns on itself. The bonds of fellowship, kinship, and covenant dissolve. "No man spares his brother." The most basic loyalties are incinerated. Every man becomes an island, and every island is on fire. This is the logical end of radical individualism. When every man is for himself, every man is against his brother. The social fabric is not just torn; it is used as tinder.
The Insatiable Hunger of Sin (v. 20)
The prophet now shifts the metaphor from fire to a ravenous, self-consuming hunger. This describes the internal state of a people given over to their sin.
"They slice off what is on the right hand but still are hungry, And they eat what is on the left hand but they are not satisfied; Each of them eats the flesh of his own arm." (Isaiah 9:20 LSB)
This is a picture of desperate, frantic, and ultimately futile activity. They grab for anything they can get, from the right and from the left, but nothing satisfies. Sin promises fulfillment but always leaves you empty. It is like drinking saltwater to quench your thirst. The more you consume, the more desperate you become. This is the engine of our modern consumerist culture, is it not? A frantic grasping for the next thing, the next experience, the next purchase, that will finally make us happy. But it never does. The hunger is never satisfied.
The image then becomes even more grotesque: "Each of them eats the flesh of his own arm." This is the endpoint of a self-centered life. When you make yourself the ultimate reality, you will eventually begin to consume yourself. You feed your lusts, your ambitions, your grievances, by cannibalizing your own soul, your own future, your own relationships. You saw off the branch you are sitting on to feed the fire of your immediate desires. It is madness. It is the insanity of a society that has lost its center, which is God, and has begun to devour itself in a frenzy of insatiable appetite.
Tribalism and the Inescapable Refrain (v. 21)
This self-consuming chaos inevitably manifests in political and social fragmentation. The internal rot becomes external warfare.
"Manasseh devours Ephraim, and Ephraim Manasseh, And together they are against Judah. In spite of all this, His anger does not turn back, And His hand is still stretched out." (Isaiah 9:21 LSB)
Manasseh and Ephraim were brother tribes, sons of Joseph. They should have been the closest of allies. But in this godless inferno, they turn on each other. Brother devours brother. This is tribalism in its rawest form. When the unifying worship of the one true God is abandoned, people will find other, lesser things to unite around, and those lesser things will always put them at war with their neighbors. We see this today in our identity politics, where people are balkanized into warring factions based on race, gender, or grievance. It is Manasseh devouring Ephraim all over again.
But notice the perverse unity they find. "And together they are against Judah." They may hate each other, but they can put aside their mutual animosity for a moment if it means they can unite against the people of God. The one thing that unites the various factions of the world is their shared hatred for Christ and His covenant people. The world will always find a temporary, hellish unity in its rebellion against the throne of David and the Son of David who sits upon it.
And then comes the refrain, the tolling of the bell of judgment:
"In spite of all this, His anger does not turn back, And His hand is still stretched out." (Isaiah 9:21 LSB)
After all this horror, this fire, this cannibalism, this civil war, you would think that judgment would be complete. But it is not. This is just the beginning. God's righteous anger is not yet satisfied. His hand is still raised, not in invitation, but in preparation for the next blow. This is a terrifying word for a people who refuse to repent. There is always another stroke of the rod. There is always a deeper level of the hell they have chosen.
The Stretched-Out Hands of the Gospel
This is a bleak and terrifying passage. And if this were the only word from God, we would be without hope, left to our self-consuming fires. But this is not the only word. The hand of God is stretched out in judgment here, but the prophets also speak of a day when God's hand would be stretched out for another purpose. Isaiah himself says, "So the LORD will strike Egypt with a plague, striking and healing them. They will turn to the LORD, and he will respond to their pleas and heal them" (Isaiah 19:22).
The ultimate picture of God's stretched-out hands is not found in the judgments on Israel, but on a Roman cross outside the walls of Jerusalem. There, the Son of God, the true Israel, had His hands stretched out and nailed to the wood. On that cross, the full fury of Yahweh of hosts, the fire of His righteous anger against all our wickedness, was poured out upon His own Son.
Jesus became the fuel for the fire. He endured the ultimate social disintegration, being abandoned by His brothers. He bore the insatiable hunger and thirst of divine judgment. He took the strife of Manasseh and Ephraim, of Jew and Gentile, into His own body on the tree. He absorbed the full, unmitigated, unending stroke of God's outstretched hand of wrath, so that for all who would turn from their sin and trust in Him, God's hands could be stretched out to them in gracious invitation.
The refrain of this passage is a terror for the unrepentant. But for the Christian, that refrain has been answered and silenced at the cross. For us, because of Christ, God's anger has turned back. Because of Christ, God's hand is no longer stretched out to strike, but is now stretched out to welcome, to heal, and to save. The fire of our sin has been quenched by the blood of the Lamb. Therefore, let us flee from the self-consuming bonfire of this world and run to the only one whose outstretched hands offer not judgment, but everlasting life.