Every once in a while, I hear someone say it: they’ve seen a dramatic change in someone’s life, and exclaim that the person has made “a complete 360-degree turn.”

Darn that new math.

What they mean, of course, is a 180-degree turn, a complete turnaround, a reversal of direction. A life that’s hell-bound is suddenly pointed heavenward. And in the Bible, that takes a change of mind and heart known as repentance.

…

It’s Pentecost. The Holy Spirit has fallen upon Jesus’ apostles in Jerusalem. A crowd has gathered. Peter has just finished his first sermon, reminding the people that the prophets had said long ago that God would one day pour out his Spirit. From ancient Scripture, he convinced the crowd that Jesus was the long-awaited Messiah — and that they killed him. Having awakened their hope by announcing that the great prophesied day had finally come, he seemed to snatch that hope back by laying the guilt of the crucifixion on their shoulders.

Imagine the truth sinking in as the people listened: Wait, what? We killed the Messiah??? What have we done? What are we going to do?

They see the problem. They despair of an answer. But Peter gives them one:

“Repent, and be baptized every one of you in the name of Jesus Christ so that your sins may be forgiven; and you will receive the gift of the Holy Spirit. For the promise is for you, for your children, and for all who are far away, everyone whom the Lord our God calls to him.” And he testified with many other arguments and exhorted them, saying, “Save yourselves from this corrupt generation.” So those who welcomed his message were baptized, and that day about three thousand persons were added.  (Acts 2:38-41, NRSV)

If we imagine the scene as a first-century version of a revival meeting, we might envision an enormously successful altar call, with people coming forward in droves. But that’s probably not quite right. Peter’s sermon did indeed provoke their conscience, but he wasn’t done and neither was the crowd. Luke tells us that he continued to reason with them, encouraging them to save themselves from “this corrupt generation.”

Now there’s an interesting phrase for you. And it doesn’t mean what adults mean when they get together and moan about “what’s wrong with kids these days.”

In the gospel of Matthew, for example, the scribes and Pharisees asked Jesus for a sign — but Jesus refused because he knew that they had no intention of believing. He called them an “evil and adulterous generation” (Matt 12:39). Later, a similar scene was repeated, with the same response from Jesus (16:4). Shortly thereafter, he called their generation “faithless and perverse” (17:17).

More importantly for Acts, the same language can be found in Luke (e.g., 7:31; 9:41; 11:29-51). As the time of his crucifixion drew near, Jesus told his disciples that he would “be rejected by this generation” (Luke 17:25). He warned them of the troubles that were coming, and even wept over the impending destruction of Jerusalem (19:41-44).

“This generation,” in other words, was going to hell in a handbasket.

And that included the people who were listening to Peter on Pentecost.

But all was not lost, Peter insisted. They could repent before it was too late. The sign of their repentance would be baptism. Water baptism in itself was nothing new, but baptism in the name of Jesus was. Baptism would signify their membership in a new community that followed Jesus as its Lord, a community created by the pouring out of God’s Spirit. The people were being offered both forgiveness and the Holy Spirit as gifts from God.

All they had to do was respond to God’s call by welcoming Peter’s message and turning themselves around.

And apparently, about 3,000 of them did just that.