Bird's-eye view
What Isaiah is describing for us here is nothing less than the fruit of the gospel in the world. This is not some far off, ethereal state in a new heavens and new earth disconnected from our history. This is a prophecy about what the Messiah, the Branch from the stump of Jesse (Is. 11:1), accomplishes in time and on earth through the power of His Spirit. Many Christians have been taught to read a passage like this and immediately relegate it to "the sweet by and by." They imagine this is what things will be like after the Lord returns, after history is wrapped up. But that is to fundamentally misunderstand the nature of the kingdom Christ inaugurated at His first coming.
This passage is a glorious, poetic description of the effects of the Great Commission being fulfilled. When the knowledge of God floods the earth, it changes things. It doesn't just change the relationship between a man and his God. It changes the relationship between man and man, and as we see here, it even transforms the deep-seated enmities of the created order. This is a picture of worldwide gospel peace. It is a portrait of a victorious church, a successful gospel, and a kingdom that grows like a mustard seed until it fills the whole earth. This is postmillennialism in living color.
Clause-by-Clause Commentary
v. 6 And the wolf will dwell with the lamb, And the leopard will lie down with the young goat, And the calf and the young lion and the fatling together; And a young boy will lead them.
The prophet begins with a series of impossible images. In the fallen world, the wolf does not dwell with the lamb, it devours the lamb. The leopard does not lie down with the goat, it ambushes it. The very nature of these animals is defined by their enmity. But under the reign of the Messiah, these natures are transformed. Now, we must be careful not to be woodenly literal here. While God is certainly able to make a literal lion eat grass, the point of the prophecy is much deeper. This is covenantal imagery. He is describing the reconciliation of the most hostile forces imaginable. Think of the enmity between Jew and Gentile, slave and free, male and female. In Christ, these walls of hostility are torn down (Eph. 2:14). Former persecutors like Saul of Tarsus, a ravenous wolf, come to dwell peacefully with the sheep of Christ's flock. The gospel does not just declare a truce; it creates a new nature. And notice who presides over this peace: a young boy. This points to the upside-down nature of the kingdom, where the humble and the weak are exalted, and it is a direct pointer to the Messiah, the child who is born, the son who is given (Is. 9:6).
v. 7 Also the cow and the bear will graze, Their young will lie down together, And the lion will eat straw like the ox.
The imagery continues and intensifies. It's one thing for predators and prey to cease hostilities; it's another for them to share a meal and a bed. The cow and the bear will graze together. Their fundamental appetites are altered. The lion, a picture of ravenous power and violent consumption, will eat straw like an ox. This is a picture of total pacification. What could possibly bring about such a radical change? Only the gospel of peace. When men are converted, their desires are reordered. The rapacious greed of the swindler is transformed into generosity. The violent anger of the abuser is replaced by gentle patience. The lion eating straw is a picture of a man whose ravenous appetites have been crucified with Christ and who now finds his sustenance in the simple fodder of God's Word. The power that raised Christ from the dead is at work in us, and it is also at work in the world, taming the savage beasts of human sin and rebellion.
v. 8 And the nursing baby will play by the hole of the cobra, And the weaned child will put his hand on the viper’s den.
Here the scene shifts from the animal kingdom to the human realm, and the stakes are raised to their highest point. The most vulnerable members of the human race, nursing babies and toddlers, are brought into contact with the most insidious and deadly of creatures, the cobra and the viper. In our fallen world, this is a recipe for certain tragedy. But in the kingdom of the Messiah, the venom is gone. The serpent's fangs are drawn. The child's innocent hand on the viper's den is a picture of the seed of the woman crushing the serpent's head (Gen. 3:15). Christ has defanged the devil. He has triumphed over him by the cross (Col. 2:15). The result is a world made safe, not through the elimination of dangers, but through the removal of their power to harm. The sting of death is sin, and the power of sin is the law, but thanks be to God, He gives us the victory through our Lord Jesus Christ (1 Cor. 15:56-57). This is a world where the curse is being rolled back, where the deadliest threats are rendered harmless by the power of the reigning King.
v. 9 They will do no evil nor act corruptly in all My holy mountain, For the earth will be full of the knowledge of Yahweh As the waters cover the sea.
This final verse is the key that unlocks the meaning of the whole passage. It gives us the cause for all these glorious effects. Why will the wolf and lamb dwell together? Why will the child play safely with the cobra? Because there will be no evil or corruption in God's holy mountain, which is the Church, the dwelling place of God that is destined to fill the whole earth. And why is there no evil? The next clause gives the reason: "For the earth will be full of the knowledge of Yahweh." This is the engine of the postmillennial hope. The world is transformed not by political programs or educational reforms, but by the powerful, saving knowledge of the one true God. This is not mere intellectual data; this is the relational, covenantal knowledge that comes through faith in the gospel. And notice the scope of it. The earth will be full of this knowledge. The comparison is to the waters covering the sea, total, deep, and comprehensive saturation. This is the goal of the Great Commission (Matt. 28:18-20). Jesus has all authority, and He commanded His church to go and disciple the nations. Isaiah tells us here that this mission will not fail. It will succeed so spectacularly that the result will be a worldwide culture of righteousness and peace, a global garden where the effects of the curse are reversed and the glory of God is everywhere to be seen.
Application
The application of this text is straightforward, and it is rocket fuel for Christian mission. We are not engaged in a holding action, trying to rescue a few souls from a sinking ship before the whole thing goes under. We are on the winning side of a war that has already been decided. The victory of Christ is the central fact of history, and prophecies like this one describe the outworking of that victory in space and time.
Therefore, we should labor with great hope and confidence. We should preach the gospel, plant churches, disciple the nations, and build Christian culture, fully expecting to see the taming of the wolves and lions in our own communities. We should not be surprised when former enemies are reconciled in Christ. We should expect to see the venom of sin neutralized by the power of the Spirit. Our eschatology must not be a doctrine of defeat, but a doctrine of dominion. Christ is reigning now, and He will continue to reign until all His enemies are made His footstool. Our task is to be faithful instruments in His hand as He fills the earth with the knowledge of His glory as the waters cover the sea.