In John’s gospel Jesus teaches us about the work of the Holy Spirit and along with the rest of the New Testament teaching we see that the work of the Spirit is central to conversion.
No one has ever become a Christian without the Holy Spirit opening their eyes to the truth of their own spiritual state and their own need of Christ as Saviour. When Jesus spoke to Nicodemus in John chapter 3, he showed Nicodemus the necessity of the new birth. Jesus in this passage shows clearly that we need the work of the Spirit before we can have new life. Nicodemus finds the whole thing puzzling but Jesus spells out how the Spirit sovereignly works in the hearts of men. Further on in the gospel he articulates a little more about the role of the spirit in leading people to himself, Jesus says,
8 And when he* comes, he will convict the world concerning sin and concerning righteousness and concerning judgment: 9 concerning sin, because they do not believe in me, 10 and concerning righteousness, because I am going away to the Father and you will see me no more, 11 and concerning judgment, because the ruler of this world has been condemned.
Jesus here shows us that because of the Holy spirit convicts of sin and the real need of salvation. Notice how this is illustrated on the day of Pentecost,
37 Now when they* heard this,* they were pierced to the heart and said to Peter and the other apostles, “What should we do, men and brothers?” 38 And Peter said to them, “Repent and be baptized, each one of you, in the name of Jesus Christ for the forgiveness of your sins, and you will receive the gift of the Holy Spirit.
Peter preaches the gospel and the Holy spirit convicts the crowd of their need of a Saviour, it is as the Holy spirit works that people are led to Christ.
Notice how the Apostle Paul describes how salvation comes to us,
3 For we also were once foolish, disobedient, led astray, enslaved to various desires and pleasures, spending our lives in wickedness and envy, despicable, hating one another. 4 But when the kindness and love for mankind of God our Savior appeared, 5 he saved us, not by deeds of righteousness that we have done, but because of his mercy, through the washing of regeneration and renewal by the Holy Spirit, 6 whom he poured out on us abundantly through Jesus Christ our Savior, 7 so that, having been justified by his grace, we may become heirs according to the hope of eternal life.
Paul shows quite clearly that the Holy Spirit is the one who applies salvation to our hearts. Without the regenerating work of the Holy Spirit we will never know the wonders of what Christ has done for us.
In all aspects of our salvation we see that God is the one who initiates whether it be in the plan of salvation or its application.