"I believe in the Holy Spirit." This is the most forgotten member of the Holy Trinity but also the one we interact with most. It is the Holy Spirit that awakens dead sinners to be able to receive the Gospel. He flows through a congregation as the preacher preaches from the Word of God. It is him that we talk to and he guides us away from sin and closer to holiness.
Every Christian has the Holy Spirit within them. Every Christian is a recovering sinner and has no hope outside of the Holy Spirit's awakening and leadership.
One time I had a discussion with a woman about predestination and the freedom to choose. Believe it or not, as a predestinarian, I do believe that people make free decisions and that we are not robots. But I also believe that salvation, just like all of history, is planned and directed by God even down to whether I will have the ability to give my heart to Jesus or not.
Ephesians 2:1 says that all people start out dead in their sins. Imagine if I decided to throw a party and go down to a graveyard and invite the people there. They are indeed free to decide to come, but unfortunately, they are dead and cannot make that decision. First, I would have to make them alive some how and then help dig them out of their holes.
This is exactly what the Holy Spirit does when he turns a sinner into a believer. And unlike me, God can send his Holy Spirit to follow someone until they come home to him. Everyone that God saves will come to know Jesus and we will see it. Those he does not save simply remain dead. Even if they show up to church, they eventually fall away and don't return.
But the Holy Spirit is so essential to the life of a believer who still recovers that believers need to ask for his guidance and spend time in Scripture every day if they are to avoid sin and are to grow closer to holiness and to influencing other people to know Jesus.