The Anatomy of a Boast: John 13:36-38
Introduction: The Two Grammars of Loyalty
In the Christian life, we are constantly confronted with the difference between two kinds of loyalty. The first is the loyalty we manufacture ourselves, forged in the heat of our own sincere, but ultimately flimsy, emotions. It is a loyalty built on good intentions, heartfelt promises, and a profound ignorance of our own weakness. The second kind of loyalty is the kind that God gives, a loyalty that is forged in the furnace of humiliation, tested by failure, and established entirely by His grace. The first is the loyalty of a boast; the second is the loyalty of a gift.
We live in an age that idolizes the first kind. Our culture celebrates self-confidence as the highest virtue. We are told to believe in ourselves, to trust our hearts, to declare our own truth. And this sentiment has crept into the church, creating a kind of therapeutic Christianity where sincere intentions are often mistaken for genuine faith. We make our promises to God, we declare our undying allegiance, and we feel very good about it. But this is a house built on sand. It is a theology of bumper stickers and inspirational posters, and it cannot withstand the first gust of a real trial.
The passage before us this morning is a clinical, almost surgical, exposure of this first kind of loyalty. In Simon Peter, we see a man who is entirely sincere. His love for Jesus is not in question. His willingness to die is, in his own mind, an established fact. He is ready to make the ultimate sacrifice, and he says so with chest-thumping bravado. But Jesus, who knows what is in man, does not applaud. He does not commend Peter for his zeal. Instead, with devastating precision, He dismantles Peter's self-confidence and shows him what it is really made of. He shows him that a loyalty built on self-reliance is simply a denial waiting to happen.
This is not just a historical account of one disciple's epic failure. This is a mirror. In Peter's boast, we see our own. In his self-deception, we see ours. And in Christ's sovereign and gracious response, we find our only hope. For this passage teaches us a critical lesson: our security does not rest in the strength of our grip on Christ, but rather in the strength of His grip on us.
The Text
Simon Peter said to Him, “Lord, where are You going?” Jesus answered, “Where I go, you cannot follow Me now; but you will follow later.” Peter said to Him, “Lord, why can I not follow You right now? I will lay down my life for You.” Jesus answered, “Will you lay down your life for Me? Truly, truly, I say to you, a rooster will not crow until you deny Me three times.
(John 13:36-38 LSB)
Misguided Zeal (v. 36)
The exchange begins with a question from Peter, who is still trying to process Jesus's earlier statement that He is leaving.
"Simon Peter said to Him, 'Lord, where are You going?' Jesus answered, 'Where I go, you cannot follow Me now; but you will follow later.'" (John 13:36)
Peter's question is born of a genuine, if limited, affection. He can't imagine being separated from his Lord. In his mind, the mission is about staying together, about protecting Jesus, about being the right-hand man in the coming kingdom. He hears Jesus's talk of departure as a disruption to the plan he has constructed in his head. He is operating on a purely horizontal level. "Where are you going, and how can I come along?"
Jesus's answer gently corrects Peter's framework. "Where I go, you cannot follow Me now." Jesus is not just moving from one geographical location to another. He is going to the cross, into death, and through death to the right hand of the Father. This is a path that He must walk alone. He is the pioneer of our salvation, the one who must open the way. No one could go with Him because His journey was not merely a matter of travel, but of atonement. He was going to bear the wrath of God for sin, and no man could stand with Him in that.
But notice the promise appended to the prohibition: "but you will follow later." This is a profound word of grace, and Peter seems to miss it entirely. Jesus is not just predicting Peter's future martyrdom, though it includes that. He is promising Peter that the path He is about to open through His death will become the very path that Peter himself will travel into glory. The cross, which is now a barrier, will become the doorway. This is a promise of ultimate restoration and fellowship. But Peter is not listening to the "later." He is stuck on the "now."
The Anatomy of a Boast (v. 37)
Peter's inability to accept Jesus's terms leads him to make one of the most infamous boasts in all of Scripture.
"Peter said to Him, 'Lord, why can I not follow You right now? I will lay down my life for You.'" (John 13:37 LSB)
Here we see the engine of self-reliance revving up. Peter cannot fathom a limitation on his own ability. "Why can I not?" is the cry of a man who believes his will is the determinative factor. He interprets Jesus's statement not as a matter of divine necessity, but as a challenge to his personal loyalty. He thinks Jesus is underestimating his grit, his courage, his devotion.
And so he makes his grand declaration: "I will lay down my life for You." He is sincere. We must grant him that. He is not lying; he is profoundly self-deceived. He has assessed his own resources, measured his own courage, and found them sufficient for martyrdom. He believes he has what it takes. His statement is a promise, a vow, a pledge of his own strength. But the entire Christian faith rests on the fact that we do not have what it takes. Our resources are bankrupt. Our courage is a vapor. Our strength is perfect weakness.
Peter's boast is the native language of the flesh. It is the creed of every man who believes that his salvation is, at some level, a cooperative effort. He is putting his own resume on the table. He is offering his life as a qualification for following Jesus. But the gospel is not for the qualified; it is for the dead. The gospel does not say, "Pledge your life to me, and I will accept you." It says, "You have no life to pledge, so I will give you mine." Peter is trying to pay for a gift that is infinitely precious with a currency that is utterly worthless: his own resolve.
Sovereign Foreknowledge and Human Frailty (v. 38)
Jesus's response is not an argument. It is a simple, brutal statement of fact. He holds up a mirror to Peter's boast, and the reflection is not a hero, but a coward.
"Jesus answered, 'Will you lay down your life for Me? Truly, truly, I say to you, a rooster will not crow until you deny Me three times.'" (John 13:38 LSB)
The question, "Will you lay down your life for Me?" is rhetorical and dripping with a divine, sorrowful irony. Jesus takes Peter's proud declaration and repeats it back to him, not as an affirmation, but as an exposure. He is not mocking Peter; He is lovingly, painfully, showing him the truth about himself. He is showing him the vast chasm between his intention and his capacity.
Then comes the prophecy, delivered with the solemn weight of "Truly, truly, I say to you." This isn't a guess. This isn't a psychological prediction based on Peter's personality type. This is a statement of sovereign foreknowledge. Jesus knows exactly what will happen in the courtyard of the high priest. He knows the servant girl's question, the bystanders' accusations, and the precise number of Peter's denials. He knows it all before it happens because He is God.
This brings us to that great intersection of divine sovereignty and human responsibility. Did Jesus's prediction cause Peter to deny Him? No. Peter's denial was his own sinful choice, made under pressure. He was responsible. But his choice was not made in a vacuum. It was made within the sovereign plan of God. God's foreknowledge does not eliminate our responsibility; it establishes the context for it. God knew Peter would fail, and He ordained that this failure would serve a greater purpose: the demolition of Peter's pride, which was a necessary prerequisite for him to become the rock upon which Christ would build His church.
The rooster is a beautiful, earthy detail. It's a reminder that this high theological drama is taking place in the real world, on a real night, governed by the ordinary rhythms of creation. The crowing of a rooster, a mundane event, will become for Peter the divine alarm clock that awakens him from his self-deceived slumber. It will be the soundtrack to his bitter weeping, the moment when the Lord's word proves true and his own word proves to be nothing but air.
From Boasting to Brokenness
So what is the central lesson here? It is that God's grace operates most powerfully not in the realm of our strengths, but in the realm of our failures. Peter had to be undone before he could be truly used. His self-confidence was a barrier to true faith, and God, in His mercy, had to demolish it.
Peter's boast was, "I will." The foundation of his faith was his own resolve. But after the rooster crowed, after the bitter tears, after the restoration on the beach, Peter's testimony became, "He has." The foundation of his faith was no longer his own strength, but the sovereign grace of the one who had prayed for him that his faith would not fail (Luke 22:32). And it did not ultimately fail. It faltered, it collapsed spectacularly, but it did not cease to exist, because its anchor was not in Peter's heart but in Christ's intercession.
This is the story of every true Christian. We all come to Christ with our Petrine boasts. We promise Him everything. And sooner or later, God in His wisdom brings a rooster into our lives. He allows us to fail, to fall flat on our faces, to see the utter bankruptcy of our own resources. He does this not to crush us, but to save us from the one thing that will truly destroy us: our pride.
The world says, "Believe in yourself." The gospel says, "You are a disaster, so believe in Christ." Peter's failure was the best thing that could have happened to him, because it taught him this lesson. It taught him that the only loyalty that lasts is the loyalty that Christ Himself provides. Our confidence must never be in our promise to Him, but always and only in His promise to us. He is the one who says, "I will never leave you nor forsake you." He is the one who says, "My sheep hear my voice, and I know them, and they follow me. And I give them eternal life, and they shall never perish; neither shall anyone snatch them out of My hand." That is the only boast that will stand on the last day.