Acts 2:32-33,36-39,41 - "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.
“Therefore let all the house of Israel know assuredly that God has made this Jesus, whom you crucified, both Lord and Christ.” 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. For the promise is to you and to your children, and to all who are afar off, as many as the Lord our God will call.”
Then those who gladly received his word were baptized; and that day about three thousand souls were added to them.
There is television commercial by Energizer batteries that says "I've got the power." It came to mind as I was writing! More on that later.
The Apostle Peter spoke of the risen Savior whom these Jews he was addressing had seen...and killed. He talked of the promise Jesus gave of the power of the Holy Spirit that would come after He was gone. Now Peter preached to these Jews under this same newly acquired power. About 3,000 were baptized and saved after he spoke. They became believers in Jesus Christ all because this Holy Spirit pierced their hearts and brought conviction regarding their participation in killing Jesus.
Like these Jews, we are also guilty of putting Jesus on the cross. If you remember, it was the Jews and the Romans who jointly killed Him...Jews and Gentiles. We are no better. Our sin has done it. My sin helped put Him on the cross. In order to be forgiven of that sin we must confess those sins to God alone. When we hear a word of conviction and sense that conviction, it is time to respond like these people did...Repent, and be baptized in the name of Jesus Christ for the remission of sins...and you also shall receive the gift of the Holy Spirit.
This is all it really takes to convert anyone. Preaching through the power of the Holy Spirit to pierce hearts and bring conviction of sin. We shouldn't need anything more. The pure word of God. The simplicity of Christ. The conviction of sin. If it was good enough for Peter...
When we have received this Holy Spirit the Word opens up. We are able to almost see between the lines! The words are not just words anymore that we understand with our minds. They come alive within our own spirits. They remain alive through the power of the Holy Spirit and just like Energizer batteries need recharging...one also does so by immersing oneself in the Word so you too can say "I've got the power!"
We don't need programs or entertainment in our churches. Three thousand were saved just because one man preached the truth through the power of the Holy Spirit. And if Acts shares his entire sermon, it wasn't even a lot of words. It was the power behind them.
A word, a conviction, a response, an act...a new life. God is good. Those who have received will attest to this.
And he [Philippian jailer] brought them [Paul and Silas] out and said, “Sirs, what must I do to be saved?” So they said, “Believe on the Lord Jesus Christ, and you will be saved, you and your household.” (Acts 16:30-31)
Jesus tells us plainly also:
...“Most assuredly, I say to you, unless one is born again, he cannot see the kingdom of God.” Nicodemus said to Him, “How can a man be born when he is old? Can he enter a second time into his mother’s womb and be born?" Jesus answered, “Most assuredly, I say to you, unless one is born of water and the Spirit, he cannot enter the kingdom of God. ...[and] whoever believes in Him should not perish but have eternal life. (John 3:3-5,15)