Acts 2:37-39

37 When they heard this, they were pierced to the heart and said to Peter and the rest of the apostles: “Brothers, what must we do?”
38 “Repent,” Peter said to them, “and be baptized, each of you, in the name of Jesus the Messiah for the forgiveness of your sins, and you will receive the gift of the Holy Spirit. 39 For the promise is for you and for your children, and for all who are far off, as many as the Lord our God will call.”

But what did they say on the streets, near the temple of Jerusalem? The proclaimed the wonders of God. When the Spirit comes into your life and makes His power known in your life, He uses you to make known the Person of God. He has no desire and will spend no time extolling your virtues. He will not give you a three minute introduction with applause signs in the background flashing. He is not about to waste His work on naming the number of charities you have worked with. The Spirit comes to give praise, honor and glory to God. He is here to lift high the name of Jesus. He comes to draw men to the cross. He is here to change sinners into forgiven men and women. He comes to use you for the glory of God and for His kingdoms sake. He speaks through you to declare the wonders of God.

Jesus said that the Spirit will come to convince and convict the world of sin, righteousness and judgment. With regard to sin that you might know that you need the cross. With regard to righteousness that you might see the holiness of God. With regard to judgment, that you might avoid hell and be brought into right relationship with God through the shed blood of Jesus Christ for you. The Holy Spirit will announce His presence in your life so that He may bear witness to the Father.