Throughout the book of Acts, we see the early church proclaiming the gospel.  But what is the gospel?  One probable reason for the many evangelistic sermons recorded in Acts is to help us better understand the gospel and so better share the gospel.  John Stott in his commentary on Acts gives four categories of the content of the evangelistic messages, and so four categories we must include when sharing the gospel.  His four categories are: gospel events, gospel witnesses, gospel promises, and gospel conditions.  Here I want to apply his categories to the messages in Acts 2 and 3, and then to the message we share:

• Gospel Events:  We must tell others about what Jesus has done that our salvation is based on.  In Acts 2, Peter speaks of Jesus’ life, death, resurrection, and ascension.  In Acts 3, Peter focuses on Jesus’ death, resurrection, and ascension.  We too must tell others what Jesus has done to save us – especially his death and resurrection.
• Gospel Witnesses: In both Acts 2 and 3, Peter gives two witnesses to what Jesus has done.  First, he appeals to Scripture, quoting numerous Old Testament passages that point to Jesus doing exactly what he did.  Second, he appeals to his own witness of Jesus’ resurrection.  This was an essential part of being an apostle – that they had seen the risen Christ.  And the apostles have recorded their witness for us in the New Testament.  So when we share the gospel, we should use the Bible.  The prophecies and eye-witness accounts point to the truth of our message.
• Gospel Promises: In Acts 2, Peter focuses on forgiveness of sins and the gift of the Spirit.  In Acts 3, Peter rewords them as the blotting out of sin and times of refreshing (a reference to the Holy Spirit?), and then adds another: the return of Jesus for the restoration of all things.  And of course there are many more gospel promises we could mention: reconciliation, justification, new life, adoption, sanctification, and on the list goes.  When we share the gospel, we should include some of the gospel promises that would attract that person or group of people to Jesus.
• Gospel Conditions: Finally, we need to tell people how they can receive these gospel promises made possible by the gospel events as given to us by the gospel witnesses.  In Acts 2 and 3, Peter calls the people to repent, to turn from their rejection of Jesus, and as such to believe in Jesus as their Messiah and Savior and King.  We too must call people to turn from their sin to Jesus, to repent and believe.

Gospel events, witnesses, promises, and conditions.  This is the gospel presented in Acts that we present to others.