Peter was speaking to a Jewish audience (some of whom were proselytes, Acts 2:10). Some of those present were “devout men” (Acts 2:5). Everyone present knew the OT well. They did not understand the OT, for they saw it through the legalistic glasses of their rabbis. Still, they knew about the prophecies of the coming Messiah, and Peter used that to evangelize them.
Keep in mind that Luke is writing to Theophilus, a believer who already knows the saving message of John 3:16. So we shouldn’t expect Luke to tell us everything Peter said that day. He may have mentioned everlasting life for all who believe in Jesus.
Also keep in mind that most, if not all, in the crowd had either seen and heard Jesus themselves or had heard about Him from people who were in Jerusalem. Acts 2:22 quotes Peter’s words: “Jesus of Nazareth, a Man attested by God to you by miracles, wonders, and signs which God did through Him in your midst, as you yourselves also know” (emphasis added).
While the people in the crowd had heard that Jesus claimed to be the Messiah and that He guaranteed eternal life to all who believe in Him, they did not yet believe those things yet. However, the miraculous sign of believers speaking in the foreign languages of those present, along with Peter’s powerful preaching, would lead many of them to faith.
Verses 25-28 quote a messianic psalm, Psalm 16:8-11. David said that God would not keep him in Hades and that He would not allow His Holy One, the Messiah, to see corruption. Unlike David, the Messiah would not decay. He would not be dead long enough for decay to occur. Psalm 16 proves that the Messiah had to die and rise from the dead.
As the people heard these words, the message made sense to some of them for the first time. Imagine how exciting that must have been.
Some of them were probably born again at this point.
Others were likely born again as Peter explained in vv 29-33.
Still others probably came to faith when he quoted and explained Psalm 110:1 in vv 34-36.
Why didn’t Peter quote John 3:16?i Because the audience already knew that message, though they did not yet believe it. Their problem was that when Peter started speaking, they still believed Jesus was a false Messiah. Peter needed to prove that the Messiah had to die and rise from the dead. When he did that, 3,000 came to believe that Jesus is the Christ (Acts 2:41), meaning that they believed He is the Guarantor of everlasting life (John 20:31).
Many do not realize that the question, “Men and brethren, what shall we do?” (Acts 2:37), was asked by new believers, not by unbelievers. They didn’t ask, “What shall we do to be saved?” Contrast their question with that of the Philippian jailer in Acts 16:30.
The fact that they were “cut to the heart” (v 37) shows that they now believed that Jesus is the Christ and that they had been guilty of helping to crucify Him.
Peter’s answer in Acts 2:38 concerns fellowship with God, not everlasting life. They were already born again. But they had yet to receive the Spirit (like the new Samaritan believers in Acts 8:12-17, who did not receive the Spirit until Peter and John laid hands on them) or to be forgiven for crucifying the Messiah. They had to repent and be baptized in order to gain fellowship with God and receive the Spirit. It wasn’t until Acts 10:43-48 that forgiveness and the reception of the Spirit occurred the moment one believed in Jesus for everlasting life. See this journal article by Lanny Thomas Tanton.
Readers of the book of Acts must keep in mind that it records a transitional time. Things were changing. In the OT, no one was baptized into the Body of Christ or permanently indwelt by the Holy Spirit. By Acts 10:43-48, both Spirit baptism and permanent indwelling occurred at the moment a person believed. But before that, both occurred after the new birth.
Consider the apostles. They were born again nearly four years before they received the Spirit and were baptized into the Body of Christ.
Keep grace in focus, and God’s Word will keep opening to you like a beautiful flower (Luke 24:32, 45).
i It is possible that he did. However, it is unlikely Luke would have failed to report that.
