“You have been purified from sin; you have been dedicated to God; you have been put right with God by the Lord Jesus Christ and by the Spirit of our God”. 

1 Cor 6:11 GNB 

Today Christians are remembering and celebrating the coming of the Holy Spirit upon the first disciples in Jerusalem. There was the sound of a rushing mighty wind, there were tongues of fire and the disciples spoke in foreign languages. And three thousand people were converted from Judaism to Christianity. 
In his first letter to the Corinthians Paul responded to many problems the Corinthian Christians were experiencing. Many forms of sinfulness were manifesting themselves in the society around them and some Christians were finding it hard to avoid relapsing into their old ways. “But”, Paul says, “Christ has put you right with God and because the Holy Spirit is working in you, you no longer have anything to do with those evil ways”. 
In other words the Holy Spirit has made them new people in Christ. That is his prime role – to make people holy, to change bad people into good people. It is called sanctification. It means to make people more like Jesus. Pentecost is about God putting his sanctifying Spirit into ordinary people to ensure that their lower, base desires and weaknesses do not rule in them, but Jesus does. 
The creation of holy people after the likeness of Jesus is still the Holy Spirit’s work today, however strongly the emphasis may be placed on spiritual gifts in some Christian circles. We proclaim Jesus, we teach Jesus and we live Jesus. In this sense there are Holy Spirit-filled Christians in all churches – whether they talk much about the Spirit or not. 

O come and dwell in me, Spirit of power within!
And bring the glorious liberty from sorrow, fear, and sin.
– C. Wesley