Acts 3:17-21 meaning

Peter, surrounded by Jews who are amazed that he just healed a lame man in the temple courtyard, continues his confrontational sermon. After reminding them that they helped put Jesus to death, and that Jesus was resurrected, and by Jesus's power the lame man was healed, Peter says And now, brethren, I know that you acted in ignorance, just as your rulers did also. They did not comprehend what they were doing when they called for Jesus to die. In reality, they were killing their own hopes and dreams.

This is consistent with what Jesus said from the cross, "Father, forgive them; for they do not know what they are doing" (Luke 23:34). And it is consistent with what Peter had already experienced, because he was a traitor too. Three times he denied any association with Jesus when Jesus was suffering torture, trial, and crucifixion. But Peter himself had his fellowship restored, because God's mercy is never-ending (John 21:155-19).

Earlier, in Acts 1:3, we learned that Jesus gave the apostles a forty-day seminar on the kingdom of God after He rose from the dead:

"To [the eleven disciples] [Jesus] also presented Himself alive after His suffering, by many convincing proofs, appearing to them over a period of forty days and speaking of the things concerning the kingdom of God."
(Acts 1:3)

Essentially, Peter and the other apostles sat through a forty-day intensive training on the Kingdom of God taught by Jesus before He went back to Heaven. Christ also explained to the apostles how He fulfilled the Old Testament prophecies, "all things which are written about Me in the Law of Moses and the Prophets and the Psalms must be fulfilled" as well as giving them understanding of the Scriptures when He, "opened their minds to understand the Scriptures" (Luke 24:44-45). Here Peter tells his Jewish audience, But the things which God announced beforehand by the mouth of all the prophets, that His Christ would suffer, He has thus fulfilled. Peter is taking the lesson he (at last) learned from Jesus, and is spreading it to others.

There are many, many prophecies of Jesus in the Old Testament, some of which are that the Messiah would be born in Bethlehem (Micah 5:2), be sold for silver (Zechariah 11:12-13a), His garments would be torn (Psalm 22:18), He would suffer abuse (Psalm 129:3), His hands and feet would be pierced (Psalm 22:16), to name just a few. But the Old Testament also predicts that the Messiah will set up His kingdom on earth, and restore the throne of David to become a perpetual kingdom (2 Samuel 7:16; Zechariah 14:4).

Jesus' special teaching to the apostles about the Kingdom of Heaven may be where Peter gets some of the content of his sermon, especially when he says: Therefore repent and return, so that your sins may be wiped away, in order that times of refreshing may come from the presence of the Lord; and that He may send Jesus, the Christ appointed for you, whom heaven must receive until the period of restoration of all things about which God spoke by the mouth of His holy prophets from ancient time.

This statement is easily overlooked. Had the Jewish people done as Peter called them to, to repent and return, the result would have been that not only would their sins be wiped away, but times of refreshing would come. The refreshing would be sent from the presence of the Lord, and the person whom the Lord would send would be Jesus, the Christ appointed for you. What was the Christ appointed to do for Israel? Bring about the period of restoration of all things. This restoration of all things includes ending sin and death upon the earth, and restoring nature (2 Peter 3:13; Revelation 21:1-4; Romans 8:22).

The Apostle Paul writes about how creation itself is longing and groaning for redemption and restoration, ever since the Fall in the garden of Eden (Romans 8:19-20). Christ's kingdom will be an everlasting kingdom of everlasting righteousness, as Peter emphasized in his second epistle (2 Peter 3:13). This is something which God spoke by the mouth of His holy prophets from ancient time (Daniel 7:27, Daniel 9:24).

Peter is telling them, 'If you will repent and if Israel will repent, Jesus will come back now and take the throne of David (2 Samuel 7:16). He's just waiting for you to receive Him.' It is a stunning statement. What that means is that if that had happened, those of us in the present age might never have been born. There might never have been an Age of the Gentiles (Romans 11:25).

Paul speaks of this in Romans 11:11a:

 "I say then, [Israel] did not stumble so as to fall, did they? May it never be! But by their transgression salvation has come to the Gentiles...
(Romans 11:11a)

The transgression of the Israelites is that they never repented, they did not turn away from wickedness. Instead, they followed their own way. They refused to follow God's way, saying, 'We're waiting for the Messiah, but he has to fit in to our plans.' Instead of receiving God's Anointed, they put God's Messiah and Son to death. But this rejection meant that salvation came to the Gentiles (Romans 11:11a).

Paul goes on in Romans 11 to make the point that if the Jews' rejection brought salvation to the Gentiles, their restoration is certain, and will be even better than it would have been:

"Now if their transgression is riches for the world and their failure is riches for the Gentiles, how much more will their fulfillment be!"
(Romans 11:12)

Israel is still God's people, and all the things that have been promised to them are still going to happen:

"…for the gifts and the calling of God are irrevocable."
(Romans 11:29)

In fact, "all Israel will be saved" (Romans 11:26). But at the time of Acts 3, the refusal of the Jews to repent and receive Jesus as their Messiah meant that Jesus did not return at that time, which allowed the Gentiles to be blessed through the spread of the gospel to them. Much of Acts will show this, as will Paul's epistles. Jesus will most certainly return in the future. Peter predicted this would be doubted.

In Peter's second epistle, he made a prediction about skeptics arising, dubious that Jesus would actually return:

"Know this first of all, that in the last days mockers will come with their mocking, following after their own lusts, and saying, 'Where is the promise of His coming? For ever since the fathers fell asleep, all continues just as it was from the beginning of creation.'"
(2 Peter 3:3-4)

Peter answers this skepticism by pointing out that God has delayed the return of Jesus as a manifestation of His mercy:

"The Lord is not slow about His promise, as some count slowness, but is patient toward you, not wishing for any to perish but for all to come to repentance."
(2 Peter 3:9)