What do you do when you realize you've killed the Messiah? That's not a hypothetical question — it's exactly the crisis that broke open on the Day of Pentecost. Peter had just finished one of the most devastating sermons ever preached, and the crowd standing in Jerusalem wasn't debating theology or taking notes. They were cut to the heart. And out of that moment of broken conviction came a question that still echoes across every generation: "Brothers, what should we do?" Peter's answer is what we're looking at this week, and it's one of the most important passages in the entire book of Acts — not just for what it says about Pentecost, but for what it says about how God actually saves us.
The Sermon That Stopped a Crowd Cold
We've been working through Peter's Pentecost sermon for a few weeks now, and last week we landed on the gut-punch ending. Peter looked at the crowd — the same Jerusalem crowd that had called for Jesus' crucifixion just fifty days earlier — and he said, essentially: the one God raised and glorified? You killed him. Not a gentle nudge. Not a soft pastoral suggestion. A declaration. And it landed exactly as hard as it was meant to.
What's remarkable is how many of those people clearly believed him. They had already witnessed the signs — the sound like a rushing wind, the tongues of fire, the disciples speaking in languages they had never learned. They had heard Peter's exposition of the prophets. Something was happening that nobody could explain away, and Peter had named it plainly: this is the fulfillment of everything God promised. Jesus of Nazareth is the Christ. And you handed him over to be crucified.
That's the backdrop for what comes next. These aren't people who are intellectually curious about Christianity. These are people who have been confronted with the reality of what they've done and who Jesus is. And so they ask the only honest question left: what do we do now?
Peter's Answer: Repent and Be Baptized
Peter doesn't hesitate. He doesn't soften the moment or give them a menu of options. He answers directly, and his answer is given to us in Acts 2:38–39:
"Repent and be baptized, every one of you, in the name of Jesus Christ for the forgiveness of your sins. And you will receive the gift of the Holy Spirit. For the promise is for you and for your children and for all who are far off, everyone whom the Lord our God calls to himself."
There's a lot packed into those two verses, and we're going to take them seriously — because Peter clearly intended them to be taken seriously.
What Repentance Actually Means
Peter's first word is repent. We throw that word around a lot in church, and sometimes the repetition dulls the edge of it. So it's worth slowing down and asking what it actually means. The word in the Greek carries the idea of turning around — a complete change of direction. Eugene Peterson, the theologian and Bible translator who passed away just a few years ago, described repentance as changing the way you think and act — turning away from the patterns of this world and reorienting your whole life according to the will and kingdom of God.
That's not a minor adjustment. That's not tweaking a few bad habits. It's a fundamental reorientation of who you are and what you're living for. And for the people standing in front of Peter that day, the Word had already done the first part of the work. They believed. They had heard the gospel proclaimed — that Jesus died and rose again, that he is the Christ — and faith had taken root. But faith always has a direction. It turns you. And Peter is naming that turning: repent. Step away from the ways that led to this moment. Turn toward the God who is offering you forgiveness in spite of it.
That's the beauty underneath the weight of that word. Repentance isn't just a demand — it's an invitation. It's God saying, there is a different way to live, and I'm making it available to you right now. The Word had created faith in the hearts of those people, and faith moves. It doesn't sit still. It turns away from sin in order to turn toward the One who has conquered it.
Baptism Is Not a Symbol
Now here's where I need to be direct with you, because this is the part of the passage that a lot of our Christian brothers and sisters get wrong — and I don't say that to be uncharitable, because I know they love Jesus. But Peter is unequivocal here, and we don't do anybody any favors by softening what he says.
There's a widespread teaching in American Christianity that baptism is essentially a symbol — something I do to demonstrate my faith publicly, a way of showing my commitment to God. Under that view, what matters is the internal decision, and the baptism is just an outward sign pointing to something that already happened inside me. It's a ceremony. A declaration. My act.
Peter doesn't say that. Not even close. He says, be baptized for the forgiveness of your sins. The forgiveness comes through the baptism. This is the place where God is working. Baptism isn't you showing God something — it's God giving you something. And in case there's any doubt about whether Peter held this view consistently, later in his life he writes a letter to the church — what we now call 1 Peter 3:21 — and he says it even more plainly: baptism now saves you. Not baptism as a symbol. Not baptism as a gesture. Baptism saves you.
This is one of the places where God has chosen to do His work. He works through the Word. He works through the sacraments. And through those means, He delivers forgiveness and life and salvation to believers. The faith that receives these gifts is itself given by the Holy Spirit — it's not something you manufacture and then bring to the water. The whole thing is God's doing, from first to last. Baptism is one of the channels through which that grace flows.
I think part of the reason people resist this is that it feels too passive — like we're not doing enough, like there's nothing left for us to contribute. But that discomfort is actually pointing us toward something true and wonderful about the gospel: salvation is not your contribution. It's God's gift. And He gives gifts through specific, concrete, physical means — like water and Word and the name of Jesus Christ.
The Promise Is For Your Children
Peter doesn't stop with individuals. He widens the scope dramatically: the promise is for you and for your children. And I want to pause on that, because it matters enormously for how we think about infant baptism — a topic that's sometimes treated like a denominational quirk rather than a serious biblical conviction.
There's a significant portion of the Christian world that holds that baptism should only be administered to people who are old enough to make a conscious decision for Christ. The idea is that faith has to come first, and then baptism follows as a response. Children, under this view, aren't ready yet — they can't make that commitment, so they have to wait. And sometimes when you hear Christians in that tradition talk about their own kids, there's this awkward category: the child isn't quite a Christian yet, but maybe someday when they're old enough...
Peter's language doesn't support that category. He says the promise is for your children. Full stop. Not "for your children when they're old enough." Not "for your children once they can articulate the gospel." For your children.
And this fits perfectly with how God has always operated. In the Old Testament, little boys became children of the covenant at eight days old through circumcision. Not when they were old enough to understand what the ceremony meant. Not when they could recite the Torah. Eight days old. The covenant was established by God's action and God's promise — not by the child's intellectual grasp of what was happening. There was no concept of an "age of accountability" in the Old Testament, because the whole framework assumed something different: you're born into this world with a sinful heart, and the grace of God needs to reach you there, at the very beginning, not after you've spent years accumulating the wreckage of a life lived without Him.
Jesus himself, when his disciples tried to keep children away from him, said let the children come to me — and the word in the Greek can mean infants, babies. Not just older children who could follow a conversation. Babies. He welcomed them. He blessed them. And the Spirit who creates faith is not limited by age or cognitive development. Faith takes hold of promises, and even an infant can be the recipient of a promise that God has spoken over them.
This is one of the reasons we baptize babies at Gloria Dei, and it's one of the reasons I'm confident every time I pour water over a child's head in the name of the Father and the Son and the Holy Spirit. God has committed himself to that child. That's not a symbol. That's a sacrament.
All Who Are Far Off — God Does the Calling
Peter's promise keeps expanding. Not just for you. Not just for your children. But for all who are far off, everyone whom the Lord our God calls to himself.
Please don't read past that last phrase. God calls. Not "everyone who figures out the right way to come to God." Not "everyone who makes the right decision at the right moment." Everyone whom the Lord calls. The initiative is God's. The power behind the call is God's. The faith that responds to the call is given by God.
What Peter did on that day was stand up and proclaim the Word. And through that Word, God called people to believe, and He gave them the faith to take hold of His promises in Christ — to see that Jesus is the Messiah, that He is the Savior, that He has the authority to forgive sins and give new life through his death and resurrection. The preaching was the instrument. The power behind it was entirely God's.
This matters for how we understand salvation from beginning to end. It's not a cooperative effort where God does His part and you do yours. It's God's work from first to last. He calls. He gives faith. He forgives. He sends the Spirit. He brings you into His community. Your response — your repentance, your coming to baptism, your living in that faith — those are real, but they are themselves the fruit of what God has already done in you. Salvation belongs to the Lord.
Saved From a Crooked Generation
Acts 2:40 tells us that Peter kept going — he had much more to say beyond what Luke records in verses 38 and 39. But the summary Luke gives us is pointed: Save yourselves from this crooked generation. And then, in verse 41: So those who received his word were baptized, and there were added that day about three thousand souls.
That phrase — "save yourselves from this crooked generation" — isn't Peter walking back what he said about God being the one who saves. It's Peter calling people to step away from one way of living and step into another. It's a call to belong to a different community, to be shaped by different values, to find your identity in Christ rather than in the culture around you.
And the temptations Peter was warning that first-century crowd about are not so different from the ones pressing in on us today. We live in a culture saturated with materialism — the quiet assumption that enough money, enough comfort, enough stuff will eventually satisfy the hunger in your soul. We live in a culture obsessed with power and influence, where politics becomes a kind of religion and people give their entire emotional and spiritual lives over to it. We live in a culture that has largely abandoned any sexual ethic rooted in God's design — where cohabitation is the default, where pornography is normalized, where the body is treated as a consumer product rather than a temple of the Holy Spirit.
Peter's warning is as sharp now as it was then: these things erode your faith. They don't just make you a little worse as a person — they corrode your relationship with God. They pull you away from the community of grace and back into the patterns of a world that is passing away. Save yourself from this generation. Repent. Turn away from those things and toward the One who offers you something this world categorically cannot give.
And notice that Peter's call to repentance is rooted in the salvation Christ has already won, not in moral self-improvement for its own sake. We're not repenting because we need to earn God's favor or because we're trying to prove something. We're repenting because there is something better — because forgiveness is real, because new life is real, because the kingdom of God is not a metaphor. When you know that Jesus has already won your forgiveness and conquered death, turning away from sin stops feeling like loss and starts feeling like freedom.
Three Thousand Souls and What That Means for the Church
Three thousand people were baptized that day. Three thousand. I'll be honest with you — we get around two hundred people on a weekend at Gloria Dei, and when I try to picture what it would look like to receive three thousand new members in a single afternoon, it's simultaneously glorious and a little overwhelming. The logistics alone — the catechizing, the pastoral care, the sheer number of baptisms — would be staggering.
But think about what was behind that number. This was fifty days after Jesus was crucified. In the week leading up to his death, Jesus had been teaching and preaching throughout Jerusalem. Many of the people standing in that crowd on Pentecost had probably heard Jesus himself — in the temple courts, in the streets, on the hillsides. The seeds had been planted. And now, as the Spirit came with power and Peter stood up and proclaimed the risen Christ, that was the final tipping point. The Spirit moved through the Word, faith took hold, and the crowds came to be baptized.
Luke says they were "added" to the disciples — and that's a word worth sitting with. They didn't just receive an individual spiritual experience and then go home to live private Christian lives. They were incorporated into a community. They became part of something. The church isn't an optional add-on to personal faith; it's the community that faith creates. When God saves you, He doesn't just change your internal spiritual status — He brings you into a body of people who are living out that salvation together.
That's why Peter's call to "save yourselves from this crooked generation" is inseparable from baptism and the community it creates. You can't truly step away from one way of living without stepping into another. You were never meant to navigate the Christian life alone. We are meant to be together — worshipping together, hearing the Word together, holding each other accountable, carrying each other's burdens. That's what the church is. And every time someone is baptized and received into this community, that three-thousand-soul day in Jerusalem echoes forward through time.
What This Means for You
So here's where all of this lands. Peter's answer to "what should we do?" was not complicated, but it was complete: repent and be baptized for the forgiveness of your sins, and you will receive the gift of the Holy Spirit. The promise is for you, for your children, for everyone God calls to himself — which turns out to be people from every generation and every corner of the earth.
If you were baptized, that moment was not a symbol. Something real happened. God put His name on you. He forgave your sins through water and Word. He gave you His Spirit. And all of that was His doing, not yours — which means the assurance it gives you doesn't depend on how strong your faith feels on any given day, or whether you can remember making a decision, or whether your spiritual life looks impressive from the outside. The promise was spoken over you, and it stands.
And the repentance that Peter calls for — that's not a one-time event any more than faith is. It's the ongoing shape of the Christian life. Every day we turn away from the pull of this world, and every day we turn back toward the God who has already claimed us. Not to earn anything, but because we've been given everything. The forgiveness Jesus won is the ground we stand on, and repentance is simply the daily practice of actually standing on it — refusing to go back to the old ways, trusting that what God has promised is better than anything this world is selling.
Take a moment today and think about your baptism — whether you remember it or not. Thank God for what He did there. And then ask yourself: in what specific ways is He calling you to repent right now? What patterns of this crooked generation are still pulling at you? What would it look like to step more fully into the community of grace He has placed you in?
Transcript generated with AI. Original by the author.
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