Who is Peter addressing in Acts chapter 3, and is he still on covenant ground?
In Acts chapter 3, Peter is addressing the nation of Israel, not Gentiles, and he is still on covenant ground. He appeals to Israel regarding their promised King, because God had not yet set them aside despite their rejection of Christ.
Les explains that Peter, shortly after Pentecost, is still addressing the nation of Israel, and the language shows he remains on covenant ground. Les ties this to the Abrahamic covenant, which he calls the bedrock of God's redemptive work: God called Abraham, promised him a nation, a land, and eventually their King and kingdom, making Israel the means of evangelizing the nations. Though Israel rejected and killed their King, God did not give up on them. In these early chapters of Acts, Peter keeps pleading with Israel, declaring that the One they killed was the One they should have accepted, that God raised Him from the dead and called Him back to glory, and that God was ready to send Him back as their King if they would believe.