Read Acts 3.
God used the miracles to validate the message. Peter and John healed this man whom everyone knew had been lame since birth. The news spread and a crowd gathered. This provided a spontaneous preaching opportunity.
In some fifteen verses, we have a full gospel presentation to the people of Israel. Here Peter synthesized the key Old Testament prophecies and declared that Jesus is the Messiah. The key elements are all here.
1. The Gospel. (v.15)
The Apostle Paul defined the Gospel as: "that Christ died for our sins in accordance with the Scriptures, that he was buried, that he was raised on the third day in accordance with the Scriptures" (1 Corinthians 15:1-3).
2. Personal Repentance. (v.19 and 26)
Turning from one's sin and turning to Jesus by faith in Him alone results in forgiveness by God; "blotted out," literally "to obliterate" or wipe away one's sin debt.
3. National Restoration. (vv. 20-21)
All the prophecies concerning a future king and the restoration of the kingdom on earth will be fulfilled when Jesus returns. That kingdom will last for one thousand years (Revelation 20:1-6).
4. The Promised Prophet. (v.22-23)
Peter claimed that Jesus was/is that person of whom Moses prophesied in Deuteronomy 18.
5. The Abrahamic Covenant. (v.25)
God has not forgotten nor reneged on His everlasting promises to Israel. In Genesis 12, 15 and 17, God made an unconditional, one-party covenant. It included:
-Land. The boundaries are given in Genesis 15:18-20.
-Descendants. The family of Abraham would become innumerable.
-Blessing. God promised to bless those who bless Abraham's descendants and curse those who curse them. In addition, "in you all the families of the earth will be blessed." Humanly, Jesus is a descendant of Abraham and by faith in Him we get to enjoy the blessing.
6. To the Jews First. (v.26)
The Gospel was always intended to be offered to the entire world (John 10:16). But the good news of Jesus began here with the Jews. The Apostle Paul wrote to the Roman believers, "For I am not ashamed of the gospel, for it is the power of God for salvation to everyone who believes, to the Jew first and also to the Greek." (Romans 1:16)