The full gospel is the power of God unto salvation.
Many are deceived into believing, that you should just ask Jesus into your heart – and everything is fine.
If we should ever come back to the life we read about in the book of Acts, we need to have the right foundation. In John 3 Jesus says, that if any man want to be born again, he need to be born out of water and Spirit. Jesus didn’t talk about the sinners prayer; he preached repentance towards God. When he then did the teaching, he talked about the importance of baptism in water and Holy Spirit.
At that time he could not himself baptize anyone to Christ and with the Holy Spirit, because it was still the old covenant. But after the cross you see the fulfillment of the new birth Jesus was talking about in John 3. When Peter stood up and said repent, as Jesus did, and be baptized for the remission of your sin as Jesus has commanded us to do it. Let’s obey Jesus and preach the full gospel. Let’s stop being blind leading the blind by giving something we do not find in the word of God.