John 16:28 "I came forth from the Father and have come into the world. Again, I leave the world and go to the Father."
In this final instruction Jesus kept reminding them that He was sent from God and that He must leave this earth to go back to the Father. This clearly states that He must die before He could go back to the Father in heaven. Yet they refuse to accept it because they wanted to serve Him as the King of Israel. His death would be the end of their dreams of riches, powers, recognitions,etc.
Mat 16:21 From that time Jesus began to show to His disciples that He must go to Jerusalem, and suffer many things from the elders and chief priests and scribes, and be killed, and be raised the third day.
John 14:26 "But the Helper, the Holy Spirit, whom the Father will send in My name, He will teach you all things, and bring to your remembrance all things that I said to you."
Since the Helper could bring to their remembrance all things that our Lord Jesus had said to them, then the gist in Act 2:22-36 must have been taught to them by our Lord.
Act 2:22-36 "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; whom God raised up, having loosed the pains of death, because it was not possible that He should be held by it... For David says concerning Him: 'I foresaw the Lord always before my face, for He is at my right hand, that I may not be shaken. Therefore my heart rejoiced, and my tongue was glad; moreover my flesh also will rest in hope. For You will not leave my soul in Hades, nor will You allow Your Holy One to see corruption. You have made known to me the ways of life; You will make me full of joy in Your presence.' "Men and brethren, let me speak freely to you of the patriarch David, that he is both dead and buried, and his tomb is with us to this day... Therefore, being a prophet, and knowing that God had sworn with an oath to him that of the fruit of his body, according to the flesh, He would raise up the Christ to sit on his throne, he, foreseeing this, spoke concerning the resurrection of the Christ, that His soul was not left in Hades, nor did His flesh see corruption. This Jesus God has raised up, of which we are all witnesses. Therefore being exalted to the right hand of God, and having received from the Father the promise of the Holy Spirit, He poured out this which you now see and hear. "For David did not ascend into the heavens, but he says himself: 'The Lord said to my Lord, "Sit at My right hand, till I make Your enemies Your footstool. Therefore let all the house of Israel know assuredly that God has made this Jesus, whom you crucified, both Lord and Christ."
Act 2:37-38, 41 Now when they heard this, they were cut to the heart, and said to Peter and the rest of the apostles, "Men and brethren, what shall we do?" 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."...Then those who gladly received his word were baptized; and that day about three thousand souls were added to them.
The disciples effectively convicted 3000 Jews. Please use this to evangelize those following the OT (eg. Jews, Muslims and misled Christians)