Fortress of Love, Field of Fire
Introduction: A Call to Remember
We live in an age of calculated amnesia. Our culture is desperate to forget where it came from, who its father is, and what God has said. It is a culture of chronological snobbery, convinced that the latest thing is the truest thing, and that all ancient warnings are simply the dusty relics of a less enlightened time. But the Christian faith is a religion of remembrance. Our central sacrament is a command to "do this in remembrance of me." Our Scriptures are a history of God's mighty acts, which we are commanded to teach to our children. And here, in this urgent little postcard of a letter, Jude tells us that our very survival depends on remembering what the apostles told us from the beginning.
Jude is writing to a church that is under assault, not from the outside, but from within. The barbarians are not at the gates; they are in the pews. They are part of the love feast. And their weapons are not swords and spears, but smooth words, licentious grace, and a denial of the Lord who bought them. This is why Jude's letter is so bracingly relevant. The great threat to the church in the West today is not the militant atheist pounding on the door, but the soft-spoken heretic in a clerical collar, the one who causes divisions by appealing to our "ungodly lusts," whether those lusts are for sexual autonomy, intellectual pride, or the approval of the world.
In this context, Jude gives us a battle plan. It is a plan with two essential movements. First, there is the defensive fortification. We are to build a fortress. Second, there is the offensive rescue mission. We are to charge into the field of fire. You cannot do the second if you have neglected the first. You cannot rescue others from a burning building if you have not first secured your own position. Jude's instructions here are not a series of disconnected platitudes. They are a coherent strategy for spiritual warfare, a call to be a people who are both garrisoned in the love of God and simultaneously engaged in a desperate, discerning triage on the battlefield.
The Text
But you, beloved, must remember the words that were spoken beforehand by the apostles of our Lord Jesus Christ, that they were saying to you, "In the last time there will be mockers, following after their own ungodly lusts." These are the ones who cause divisions, worldly-minded, not having the Spirit. But you, beloved, building yourselves up on your most holy faith, praying in the Holy Spirit, keep yourselves in the love of God, waiting for the mercy of our Lord Jesus Christ to eternal life. And on some, who are doubting, have mercy; and for others, save, snatching them out of the fire; and on others have mercy with fear, hating even the tunic polluted by the flesh.
(Jude 1:17-23 LSB)
Apostolic Foresight (vv. 17-19)
Jude begins by anchoring the church in the prophetic authority of the apostles.
"But you, beloved, must remember the words that were spoken beforehand by the apostles of our Lord Jesus Christ, that they were saying to you, 'In the last time there will be mockers, following after their own ungodly lusts.'" (Jude 1:17-18)
The first line of defense is to realize that none of this is a surprise. The apostles, speaking for Christ, told us this was coming. The rise of scoffers and heretics is not a sign that the Christian project has failed; it is a sign that the apostolic predictions were true. When you see men mocking the clear teaching of Scripture on creation, on sexuality, on judgment, you should not be dismayed. You should be confirmed in your faith. This is exactly what they told us would happen in the "last time," which is the entire era between Christ's first and second comings.
Who are these mockers? They are defined by their appetites: "following after their own ungodly lusts." Their theology is a rationalization for their sin. They do not arrive at their conclusions through careful exegesis; they arrive at their conclusions because their lusts demand it. They need a god who will accommodate their rebellion, so they invent one. This is the source of all theological liberalism. It begins with a lust, and it ends with a heresy to justify it.
"These are the ones who cause divisions, worldly-minded, not having the Spirit." (Jude 1:19)
Jude gives us three diagnostic markers for these false teachers. First, they cause divisions. They are spiritual schismatics. They will flatter and praise their own little cliques while despising the historic faith. They separate themselves, not for the sake of holiness, but for the sake of sin. Second, they are "worldly-minded." The Greek word is psychikos, which means soulish or natural. It describes the man living by his natural instincts and appetites, as opposed to the man living by the Spirit of God. Their wisdom is earthly, unspiritual, demonic (James 3:15). Third, and this is the root of it all, they are "not having the Spirit." They are spiritual impostors. They may have the vocabulary of faith, they may be in the church, but they are unregenerate. They are hollow men.
The Christian's Fortification (vv. 20-21)
In contrast to the destructive work of the mockers, Jude lays out the constructive duty of the saints. This is the "But you, beloved..." It is a call to build.
"But you, beloved, building yourselves up on your most holy faith, praying in the Holy Spirit," (Jude 1:20)
Notice the foundation: "your most holy faith." This is not our subjective feeling of faith. This is the objective body of truth, "the faith which was once for all handed down to the saints" (v. 3). We are to build our lives on the bedrock of apostolic doctrine, not the shifting sands of personal experience or cultural trends. This building is an active, corporate project. It is done through the preaching of the Word, through catechism, through study, through fellowship.
And this construction project is powered by prayer: "praying in the Holy Spirit." This is prayer that is aligned with the purposes of God, guided by the Word of God, and energized by the Spirit of God. It is the opposite of the self-centered, lust-driven prayers of the worldly-minded. It is a dependent, humble, and powerful communion with our God.
"keep yourselves in the love of God, waiting for the mercy of our Lord Jesus Christ to eternal life." (Jude 1:21)
Here is the central command, the keystone of the arch. "Keep yourselves in the love of God." This is a beautiful paradox that marries divine sovereignty and human responsibility. We are kept by the power of God (1 Peter 1:5), and yet we are commanded to keep ourselves. This does not mean we must earn God's love or perform in order to maintain our justification. God's love for His elect is eternal and unchanging. Rather, it means we are to remain in the sphere where that love is enjoyed and experienced. It is like telling someone to stay in the sunshine. The sun is shining regardless, but you have the responsibility to not walk into a cave. How do we do this? By the means Jude has just given us: building on the faith and praying in the Spirit. Obedience is the pathway where we enjoy the conscious warmth of God's love.
And all of this is done with our eyes on the horizon, "waiting for the mercy of our Lord Jesus Christ." Our ultimate hope is not in our ability to build or our ability to keep ourselves. Our ultimate hope is in the final act of mercy that will be revealed when Christ returns. This keeps us from pride. We are builders, but the final blueprint and the grand unveiling belong to Him. We are soldiers, but the final victory is His.
Spiritual Triage on the Battlefield (vv. 22-23)
Having secured our own fortress, we are now commanded to go out on rescue missions. But Jude insists on careful discernment. This is spiritual triage. Not every casualty is treated the same way.
"And on some, who are doubting, have mercy;" (Jude 1:22)
First, there are the doubters. These are not the arrogant mockers, but those who are wavering, confused, or troubled by the deceptions of the false teachers. They are to be treated with mercy. They need patient answers, gentle correction, and compassion. You do not amputate a limb because of a splinter. You show mercy, remembering your own weakness and the grace shown to you.
"and for others, save, snatching them out of the fire;" (Jude 1:23a)
Second, there is a category of people who are in imminent danger. They are not just doubting; they are playing with fire. They are entangled in serious sin, on the very edge of destruction. These require a different approach. The call is to "snatch them out of the fire." This is not a time for polite debate. This is a time for urgent, forceful intervention. It is a loving, desperate rescue. It might mean a sharp rebuke, a church discipline process, or a direct confrontation. It is the spiritual equivalent of tackling someone to get them out of the path of an oncoming truck.
"and on others have mercy with fear, hating even the tunic polluted by the flesh." (Jude 1:23b)
The third category is the most difficult. These individuals are to be shown mercy, but it must be a mercy tempered "with fear." Who are they? They are those who are so deeply stained by their sin that getting close to them is spiritually hazardous. The imagery is potent: "hating even the tunic polluted by the flesh." A tunic was the undergarment, worn next to the skin. The picture is of a garment so contaminated by a diseased person that you would not even touch the garment, for fear of contagion. This means we are to love the sinner but absolutely despise his sin. We show them mercy, but we do so with rigorous, holy boundaries. We do not join them in their filth in order to win them. We extend a hand of mercy, but with a healthy fear of the sin that has so thoroughly corrupted them. This is not pharisaical superiority; it is spiritual wisdom. It is recognizing that sin is a deadly and defiling disease.
Conclusion: Kept for Him
The Christian life described by Jude is anything but passive. We are to be builders, watchmen, and firefighters. We are commanded to remember the past, build in the present, and wait for the future. We are to fortify ourselves in the truth and love of God, so that we might be equipped to engage in the dangerous and discerning work of rescuing others.
We build ourselves up on the faith. We pray in the power of the Spirit. We live in the sunshine of God's love. We look for the mercy of Christ's return. And as we do, we extend mercy to the doubter, we snatch the endangered from the fire, and we cautiously show mercy to the contaminated, all while hating sin with a perfect hatred.
This is a high and difficult calling. But we must remember how Jude's letter ends. He commits us to the one "who is able to keep you from stumbling, and to make you stand in the presence of His glory blameless with great joy" (v. 24). We keep ourselves in His love, because He is the one who ultimately keeps us. We fight, because He has already won the war. We work, because our final presentation before the throne is His work. So let us be about our duty with courage and with joy, fortified and fearless.