1) Peter used the prophecy of Joel 2:28-32 in support of Pentecost.
Acts 2:17-21 “And it shall come to pass in the last days, says God, that I will pour out of My Spirit on all flesh; Your sons and your daughters shall prophesy, Your young men shall see visions, Your old men shall dream dreams. And on My menservants and on My maidservants I will pour out My Spirit in those days; And they shall prophesy. I will show wonders in heaven above and signs in the earth beneath: Blood and fire and vapor of smoke. The sun shall be turned into darkness, and the moon into blood, before the coming of the great and awesome day of the LORD. And it shall come to pass That whoever calls on the name of the LORD Shall be saved.”
Note: This prophecy is about the last days before the return of Jesus Christ to the earth.
Matthew 24:29-30 “Immediately after the tribulation of those days the sun will be darkened, and the moon will not give its light; the stars will fall from heaven, and the powers of the heavens will be shaken. Then the sign of the Son of Man will appear in heaven, and then all the tribes of the earth will mourn, and they will see the Son of Man coming on the clouds of heaven with power and great glory.”

2) Peter accused the Jewish people of the murder of Jesus Christ.
Acts 2:22-23 “Men of Israel, hear these 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; him, being delivered by the determined purpose and foreknowledge of God, you have taken by lawless hands, have crucified, and put to death;”
Note: God gave His Son as a sacrifice for our sins from the beginning of time.
John 3:16 “For God so loved the world that He gave His only begotten Son, that whoever believes in Him should not perish but have everlasting life.”
Romans 5:8 But God demonstrates His own love toward us, in that while we were still sinners, Christ died for us.
1 Corinthians 15:3 For I delivered to you first of all that which I also received: that Christ died for our sins according to the Scriptures.
1 Thessalonians 5:9-10 For God did not appoint us to wrath, but to obtain salvation through our Lord Jesus Christ, who died for us, that whether we wake or sleep, we should live together with Him.
Revelation 13:8 All who dwell on the earth will worship him, whose names have not been written in the Book of Life of the Lamb slain from the foundation of the world.
Note: We are not to judge people.
Matthew 7:1-2 “Judge not, that you be not judged. For with what judgment you judge, you will be judged; and with the measure you use, it will be measured back to you.”
Romans 2:1 Therefore you are inexcusable, O man, whoever you are who judge, for in whatever you judge another you condemn yourself; for you who judge practice the same things.
Romans 14:10 But why do you judge your brother? Or why do you show contempt for your brother? For we shall all stand before the judgment seat of Christ.
James 4:12 There is one Lawgiver, who is able to save and to destroy. Who are you to judge another?

3) Peter said that Jesus was made into the Christ.
Acts 2:36 “Therefore let all the house of Israel know assuredly that God has made this Jesus, whom you crucified, both Lord and Christ.”
Note: Jesus was the Christ from before time.
Micah 5:2 “But you, Bethlehem Ephrathah, Though you are little among the thousands of Judah, Yet out of you shall come forth to Me The One to be Ruler in Israel, Whose goings forth are from of old, From everlasting.”
Matthew 1:22-23 So all this was done that it might be fulfilled which was spoken by the Lord through the prophet, saying: "Behold, the virgin shall be with child, and bear a Son, and they shall call His name Immanuel," which is translated, "God with us."
John 1:1 In the beginning was the Word, and the Word was with God, and the Word was God.
John 1:14 And the Word became flesh and dwelt among us, and we beheld His glory, the glory as of the only begotten of the Father, full of grace and truth.
John 8:58 Jesus said to them, “Most assuredly, I say to you, before Abraham was, I AM.”
Philippians 2:5-7 Let this mind be in you which was also in Christ Jesus, who, being in the form of God, did not consider it robbery to be equal with God, but made Himself of no reputation, taking the form of a bondservant, and coming in the likeness of men.
Hebrews 1:10-12 And: “You, LORD, in the beginning laid the foundation of the earth, And the heavens are the work of Your hands. They will perish, but You remain; And they will all grow old like a garment; like a cloak You will fold them up, And, they will be changed. But You are the same, And Your years will not fail.”
Hebrews 13:8 Jesus Christ is the same yesterday, today, and forever.

4) Peter declared that baptism was necessary for salvation.
Acts 2:38 Then Peter said to them, “Repent, and let every one of you be baptized in the name of Jesus Christ for the remission of sins; and you shall receive the gift of the Holy Spirit.”
Note: Paul declared that confession not baptism was necessary for salvation.
Romans 10:8-13 But what does it say? "The word is near you, in your mouth and in your heart" (that is, the word of faith which we preach): that if you confess with your mouth the Lord Jesus and believe in your heart that God has raised Him from the dead, you will be saved. For with the heart one believes unto righteousness, and with the mouth confession is made unto salvation. For the Scripture says, "Whoever believes on Him will not be put to shame." For there is no distinction between Jew and Greek, for the same Lord over all is rich to all who call upon Him. For "whoever calls on the name of the Lord shall be saved."
1 Corinthians 1:17-18 For Christ did not send me to baptize, but to preach the gospel, not with wisdom of words, lest the cross of Christ should be made of no effect. For the message of the cross is foolishness to those who are perishing, but to us who are being saved it is the power of God

5) Peter's "end of the world" message brought slothfulness and poverty.
Acts 2:44-47 Now all who believed were together, and had all things in common, and sold their possessions and goods, and divided them among all, as anyone had need. So continuing daily with one accord in the temple, and breaking bread from house to house, they ate their food with gladness and simplicity of heart, praising God and having favor with all the people. And the Lord added to the church daily those who were being saved.
Note: Paul had to take up a collection for the poor saints in Jerusalem.
Romans 15:25-26 But now I am going to Jerusalem to minister to the saints. For it pleased those from Macedonia and Achaia to make a certain contribution for the poor among the saints who are in Jerusalem.
1 Corinthians 16:1-4 Now concerning the collection for the saints, as I have given orders to the churches of Galatia, so you must do also: On the first day of the week let each one of you lay something aside, storing up as he may prosper, that there be no collections when I come. And when I come, whomever you approve by your letters I will send to bear your gift to Jerusalem. But if it is fitting that I go also, they will go with me.
Note: The Millerites in 1844 thought that the end of the world was near.
The Millerites had to deal with their own shattered expectations, as well as considerable criticism and even violence from the public. Many followers had given up their possessions in expectation of Christ's return. Wikipedia
Note: The Jehovah Witnesses have been proclaiming the end of the world.
Jehovah's Witnesses teach that since October 1914, humanity has been living in a period of intense increased trouble known as "the last days", marked by war, disease, famine, earthquakes, and a progressive degeneration of morality. They believe their preaching is part of the sign, often alluding to the text of Matthew 24:14, "And this gospel of the kingdom shall be proclaimed in all the world as a witness to all nations. And then the end shall come." Wikipedia

6) Peter was wrong many other times in the New Testament.
Matthew 16:22-23 Then Peter took Him aside and began to rebuke Him, saying, “Far be it from You, Lord; this shall not happen to You!” But He turned and said to Peter, “Get behind Me, Satan! You are an offense to Me, for you are not mindful of the things of God, but the things of men.”
Mark 14:29-30 Peter said to Him, “Even if all are made to stumble, yet I will not be.” Jesus said to him, “Assuredly, I say to you that today, even this night, before the rooster crows twice, you will deny Me three times.”
Luke 22:58-60 And after a little while another saw him and said, “You also are of them.” But Peter said, “Man, I am not!” Then after about an hour had passed, another confidently affirmed, saying, “Surely this fellow also was with Him, for he is a Galilean.” But Peter said, “Man, I do not know what you are saying!” Immediately, while he was still speaking, the rooster crowed.
John 13:6-8 Then He came to Simon Peter. And Peter said to Him, “Lord, are You washing my feet?” Jesus answered and said to him, “What I am doing you do not understand now, but you will know after this.” Peter said to Him, “You shall never wash my feet!” Jesus answered him, “If I do not wash you, you have no part with Me.”
Acts 10:14-16 But Peter said, “Not so, Lord! For I have never eaten anything common or unclean.” And a voice spoke to him again the second time, “What God has cleansed you must not call common.” This was done three times. And the object was taken up into heaven again.
Galatians 2:11-14 Now when Peter had come to Antioch, I withstood him to his face, because he was to be blamed; for before certain men came from James, he would eat with the Gentiles; but when they came, he withdrew and separated himself, fearing those who were of the circumcision. And the rest of the Jews also played the hypocrite with him, so that even Barnabas was carried away with their hypocrisy. But when I saw that they were not straightforward about the truth of the gospel, I said to Peter before them all, “If you, being a Jew, live in the manner of Gentiles and not as the Jews, why do you compel Gentiles to live as Jews?”
 
7) Peter acknowledged Paul’s superior understanding.
2 Peter 3:14-16 Therefore, beloved, looking forward to these things, be diligent to be found by Him in peace, without spot and blameless; and consider that the longsuffering of our Lord is salvation—as also our beloved brother Paul, according to the wisdom given to him, has written to you, as also in all his epistles, speaking in them of these things, in which are some things hard to understand, which untaught and unstable people twist to their own destruction, as they do also the rest of the Scriptures.