In its next simplest form, it is belief in Jesus Christ. Faith really is all that matters.
Too many people (and Christian denominations) have turned this into belief in things about Christ. Faith in things about Christ, even really important things like his death on a cross, will not save you.
It seems extremely significant to me that the apostles never told a single lost person that Jesus died for their sins.
Look it up for yourself. Read the Book of Acts. I counted 12 Gospel sermons, all by apostles, in Acts, and the fact—the true, accurate, and Scriptural fact—that Jesus died for our sins is never mentioned, not even in one of them.
I'm operating on the assumption that the apostles produced true conversions and that we are to preach exactly the Gospel that they preached. I think almost all Christians agree with me on that. In fact, I'm assuming that if you are reading this book, you already agree with that as well.
The apostles told the church that Jesus died for our sins. They told the church that repeatedly, and they tell us to be grateful for it.
But they never told a lost person that.
Every mention of Jesus' death in Acts is simply a precursor to testifying that Jesus rose from the dead. While the forgiveness of sins is tied to belief in Jesus, it is never tied to believing in Jesus' sacrifice because Jesus' sacrifice is never mentioned.
There's a reason for this: The Gospel is about Jesus Christ, the person, proved to be the Son of God, the Judge of all, and the Christ of God by the resurrection from the dead.
Belief in his sacrifice is not enough.
Jesus' sacrifice is simply an explanation of how he saved us. That can wait until after we are saved, and the apostles did wait until after people were saved.
I know that's not how we tend to think nowadays, but we really don't have any fruit to indicate that we've got very much right. It should therefore be no surprise to us that we have some drastic changes to make in our preaching and our theology.
I hope that all of us have met people who are deeply in love with Jesus Christ.
These are people who talk about Jesus all the time. They believe everything he says, and they believe everything his apostles said.They trust him, they turn their lives upside down for him, and they make it clear that their lives are shaped by a radical faith in him.
Those people are happy. Those people are powerful. Those people see miracles all the time.
One of my favorite examples was Ron Rozier.
Ron Rozier was a young black man I met in the mid-80's while I was stationed in Germany. I was a follower of Christ, and as such, Ron treated me like a brother all the time.
If Ron saw me in the BX (the Base Exchange, a small, military department store), he would greet me with loud exuberance, even if I was many aisles away. He would stop what he was doing, cross the BX, and hug me, joy flowing from every pore of his skin.
Ron lived his life like that. I saw him once in the dorms. He told me he had been laying in bed when he realized that he hadn't witnessed to anyone that day. So he got out of bed and went to look for a person to witness to.
That was Ron.
I mention that Ron was black because he attended a black church. Black churches have a lot of cultural distinctions. There's a lot more testimony and general loudness than there is in white churches.
I was part of a home church that was mostly Puerto Rican. They were pretty loud, too, but I was quieter sort of Christian.
I'm sure there were differences in our theology, too. I'm sure he had interpretations of verses that I didn't agree with, and I'm sure that I had interpretations of the Bible that he didn't agree with.
We never found out, though. We were too busy praising Jesus together. We were too busy talking about those we'd witnessed to and the wonders that Jesus was working in our lives.
I haven't seen Ron Rozier in 24 years. He left Germany somewhere around 1986, when I got out of the military, and we didn't keep in contact.
Nonetheless, to this day Ron encourages me. Every time I think of him I get fired up to follow Christ exuberantly and to obey his commands.
I remember Ron telling me that he had written to his dad back in the States to tell him that he wouldn't be calling him "father" anymore. He started the letter, "Dear Dad," and then he explained that Jesus forbids us to call any man on earth our father (Matt. 23:9).
I don't agree with that interpretation of Christ's command. I think we're allowed to call our dads "father." I think Jesus was speaking about those who use "father" as a spiritual title. In fact, I think he was also talking about those who use "pastor," "reverend," or any other such word as a title.
But though I don't agree with Ron's interpretation of that verse, and I hope that he has since felt free to call his dad "father," I completely agree with Ron's interpretation of what it means to follow Christ: Go all the way; hold nothing back; risk everything.
What people call "the Great Commission" is Jesus' command to his apostles in Matthew 28:19-20. While I don't believe that commission is given to all Christians, I do believe that when we make disciples, we should do it the way the apostles did. (I think Christians that aren't sent, Rom. 10:15, should be simply obeying 1 Thess. 4:11, and living a quiet life of obedience to Christ.)
Jesus told the apostles to make disciples, baptize them, and teach them to obey everything he commanded.
Ron Rozier is still teaching me to obey everything Christ commanded, even though I haven't seen him in 24 years.
How does one preach the Gospel?
The way I just did. You tell people about Jesus. You tell them who he is. You tell them what he does, and you tell them that they, too, should believe in this man so that they can experience the forgiveness of sins and fellowship with God.
Take, for example, Peter's message to Cornelius, the first Gentile (non-Jew) convert.
Have you ever actually looked at that sermon (Acts 10:34-43)? It was so powerful that it produced converts without an altar call!
Peter begins by telling Cornelius that God accepts all those of any nation who fear him and work righteousness, something most of us don't even believe. We think God only accepts those who have heard about Jesus Christ and believed in his death for our sins.
Not true. We're wrong; Peter is right.
He then tells Cornelius that God sent a message of peace through Jesus Christ. In other words, Jesus can reconcile us to God.
After that he tells him that Jesus went about doing good and healing all those oppressed by the devil. He was able to do this because God was with him, having anointed him with the Holy Spirit and power.
Peter then says that we (the apostles, most likely) are witnesses of those things and of his death in Jerusalem. God, however, raised him up and showed him to chosen witnesses (again, the apostles), with whom Jesus ate and drank after rising from the dead.
Peter's final point is that God commanded the apostles to preach to the people that Jesus was ordained by God to be the Judge of the living and the dead, and the prophets testify that all who believe in him can receive forgiveness of sins through his name.
That's it. According to Peter, the apostles were not appointed to testify that Cornelius could receive forgiveness of sins by believing in Jesus' death. They were appointed to testify that he is the Judge of the living and the dead, proven by the resurrection, and that forgiveness of sins comes by his name.
Don't get me wrong. Jesus did die for our sins. The blood of the New Covenant—Jesus' blood—was shed so that sins could be forgiven.
Peter just didn't believe he was appointed to tell that to Cornelius or any other lost person. He was appointed to tell people about Jesus Christ.
Apparently Paul agreed with him because when Paul preached, his sermons had exactly the same content (e.g., Acts 13:26-39).
There's a really interesting verse in Acts 5.
It comes right after an angel released Peter from prison. Once he released him, he gave Peter something to do. It was:
Go. Stand and tell the people in the temple all the words of this life.
What do you think those words are?
They are words that you can speak, too. You have a testimony about Jesus Christ. In this chapter, above, I chose to give you Ron Rozier's testimony. I chose to tell you about the ability of Jesus Christ to fill a man with joy, exuberance, and obedience to God.
I chose to add to it the things the apostles said, that Jesus Christ is the Judge of the living and the dead and that if you believe in him, then you, too, can be reconciled to God and experience the forgiveness of sins.
That's the Gospel.
If you want to experience what Ron Rozier experienced, that's the Gospel you must believe. Not facts, but a person. Jesus Christ, risen from the dead, ascended into heaven, appointed Judge of the living and the dead.
He can reconcile you to God, who created you for a purpose—a purpose meant to bring you fullness of joy.
Note that I did not say "ease." It is through many tribulations that we must enter the kingdom of God. But I did say fullness of joy because you were created to obey God and live in fellowship with him.
Oh, yeah ... about that kingdom ...