Peter has called his Jewish audience to repent, so that Jesus would come back to earth and establish His kingdom. He doubles down on Old Testament prophecy to convict those in the crowd listening to him to turn from their sinfulness and return to God. The Jewish audience would know these scriptures, and would be resting their hope upon the promises of God to one day restore Israel. Peter tries to get them to understand that this promise is upon them, if they will repent.
But they were focused on the Roman occupation, and on the Messiah fitting a certain role they expected, to deliver them physically, politically. Accordingly, they did not see Jesus for who He was, their Messiah sent to deliver them spiritually. So they put Him to death. Peter argues that Jesus is the Messiah from the Old Testament, quoting Deuteronomy 18:15: Moses said, 'The Lord God will raise up for you a prophet like me from your brethren; to Him you shall give heed to everything He says to you. Peter is saying that Jesus is the prophet predicted by Moses. It is Jesus whom God raised up to fulfill this prophecy.
In the context of Deuteronomy 18, Moses speaks of the time when Israel was gathered at Mt. Sinai, where God descended on the mountain in fire, smoke, and with the sound of trumpets. But Israelites had come to Moses and said, in so many words, 'Listen, Moses, all this fire on the mountain, the smoke, the sounds, it's terrifying us. We're afraid we're going to die. Can God speak to us some other way? Let Him speak through you.'And Moses, and the Lord, heard their concern and addressed their fear. God answered their request by speaking through Moses in that time, but also by providing a promise of a future prophet, a "second Moses."
God promised to raise up a prophet like Moses who would speak to Israel with God's own mouth. Jesus fulfilled this prophecy because He was both human, like Moses, as well as God. So He spoke from God's own mouth, but without the imposing presence that made men fear for their lives; He came in the form of a mere human (Philippians 2:5-10). Because Jesus was this prophet, it was to Him that the Jews should give heed to everything He says to you.
Jesus not only spoke the words of God, like God gave from Mt. Sinai, He was the Word. He was the embodiment of the Word of God (John 1:1). The Holy Spirit's arrival to fill the disciples with God's power in the upper room was a lot like Mt. Sinai, with fire and wind and sounds, with the Holy Spirit coming into people's lives (Acts 2:2-4). Jesus was human, like Moses. But He spoke from God's own mouth, because He was God, fulfilling Moses's prophecy of Deuteronomy 18:15. After Jesus rose, defeating death, God sent His Spirit to indwell His people, writing a new covenant upon the hearts of His people (Jeremiah 3:31-33).
Peter quotes more from Deuteronomy 18, And it will be that every soul that does not heed that prophet (Jesus, the second Moses) shall be utterly destroyed from among the people. This "perverse generation" (Acts 2:40) was a generation that rejected Jesus, the Messiah, who came to redeem them. Eventually, nearly forty years after Christ ascended to Heaven, the whole nation of Israel was decimated. Jerusalem is besieged, and the temple is destroyed. Interestingly enough, the Jews who believed in Jesus were largely exiled, and thereby would have escaped this Roman devastation.
Peter is warning them, so they can avoid this judgment. They should repent, and avoid what is prophesied will happen to Israel. Peter says to the Jews: And likewise, all the prophets who have spoken, from Samuel and his successors onward, also announced these days where the Messiah returns. They have a choice to make, whether they are going to be that generation that receives the restoration, or the generation upon which this doom falls.
Perhaps in referencing Samuel, as one of the prophets who has spoken, Peter is pointing to the Davidic covenant between God and King David, "Your house and your kingdom shall endure before Me forever; your throne shall be established forever" (2 Samuel 7:16). If the people repent, Jesus will return, and set up the kingdom for Israel forever. If they do not repent, they will be utterly destroyed from among the people.
These days that Peter refers to are the days when Jesus came as the second Moses, the prophet that the Lord God sent, the One who spoke God's words to the Jewish people. Jesus Himself explained this,
"For I did not speak on My own initiative, but the Father Himself who sent Me has given Me a commandment as to what to say and what to speak."
(John 12:49)
Peter puts it to his audience that These days are "today." Jesus came, He was God's prophet, and is the bridge back to God, 'Will you follow Him now? Are you going to reject Him like you rejected God in the days in the wilderness?' (Numbers 14:20-23). Peter reminds them that they are God's chosen, covenant people: It is you who are the sons of the prophets and of the covenant which God made with your fathers, saying to Abraham, 'And in your seed all the families of the earth shall be blessed.' This last statement of Peter is a quote from Genesis, speaking to Abraham regarding his descendants. God made a covenant with Abraham, promising him that all the families of the earth would be blessed through him, and his descendent.
Who is that seed through whom all the families of the earth shall be blessed? As Paul points out in Galatians, it is not "seeds" plural, it's "Seed," singular (Galatians 3:16). The Seed that blessed all the nations of the Earth is Jesus Christ. In these days of Acts 3, He is Jesus, the second Moses, and He is the Seed promised to Abraham in Genesis 22.
"In your seed all the nations of the earth shall be blessed, because you have obeyed My voice."
(Genesis 22:18)
God made this promise to Abraham after he was willing to sacrifice Isaac in obedience to God, trusting that God would raise Isaac from the dead. It was his trust in the resurrection of Isaac that created this amazing promise. And it was the resurrection of Jesus that gives the opportunity for every person to have their iniquity put on the cross, and heal the breach between themselves and God (Colossians 2:14). That is the amazing gift of God (Romans 6:23).
Peter is actively preaching the gospel at this point. He is inviting the Jewish people to repent and reconcile with God, through Jesus Christ; For you first, God raised up His Servant and sent Him to bless you by turning every one of you from your wicked ways. Jesus came to bless Israel, and turn every one of them from their wicked ways. This is now their opportunity. Will they turn? Both John the Baptist and Jesus taught that spiritual repentance must precede physical blessing.
Physical prosperity without spiritual vibrancy is a burden. God desires to bless people. But they must choose to put themselves into a posture to be blessed. That means to turn from their wicked ways. The ways of sin are self-destructive. If God gives them more physical blessing, that just means more power to harm themselves. First He desires that they repent. Then the "times of refreshing" will be something that they can embrace, and benefit from (Acts 3:19).
