The New Birth
As Jesus engages with Nicodemus, he challenges this teacher’s grasp of God’s program of redemption. He points him from the earthly to spiritual, and prompts him to consider how the spiritual kingdom of God has made an incursion into this world of the kingdoms of men through the Christ himself. Jesus’ goal is not to make Nicodemus despair that entrance into God’s kingdom is inaccessible to him. Quite to the contrary, his goal is to focus Nicodemus on the real and tangible ways in which God’s spiritual kingdom has been made accessible through himself.
To that end, Christ’s preaching itself is one of those real and tangible ways that God’s spiritual kingdom is made accessible to us. Even with his emphasis on the sovereign direction of new birth by the Spirit, it is Christ’s preaching that makes Nicodemus aware of his need and God’s provision of his Spirit to bring about renewal and regeneration.
Sinclair Ferguson draws out an important implication of this truth: “Regeneration and the faith to which it gives birth are seen as taking place not by revelationless divine sovereignty, but within the matrix of the preaching of the word and the witness of the people of God. Their instrumentality in regeneration does not impinge upon the sovereign activity of the Spirit. Word and Spirit belong together.”
Paul made this point to the Thessalonians when he reminded them that the gospel that he preached came to them “not only in word, but also in power and in the Holy Spirit and with full conviction” (1 Thess 1:5 ESV). Indeed, this connection between Word and Spirit in Paul’s ministry to the Thessalonians is what gave him encouragement that God had chosen them (1 Thess 1:4). What Paul experienced is what we should also hope for: that the Spirit would work through our own proclamation of the gospel to bring about new birth in many of those who hear of Christ through us.
Beyond Christ’s own preaching about the kingdom requirement of spiritual new birth, our Lord also hints that this new birth is evidenced in another real and tangible way. Jesus concludes his discussion of the Spirit’s sovereign work in bringing forth new birth by suggesting that Nicodemus himself can see this happen if he opens his eyes. Jesus says, “The wind blows where it wishes, and you hear its sound, but you do not know where it comes from or where it goes. So it is with everyone who is born of the Spirit” (John 3:8 ESV). Note here that everyone who is born of the Spirit is like a tree whose leaves are rustled by the invisible and independent wind that rushes through them. You never see the wind, but you do see its effects.
Sinclair Ferguson puts it this way: “The Spirit’s presence is recognized exclusively by its effects. In one sense, therefore, we do not have access to the divine activity in regeneration, only to its immediate accompaniments. We hear ‘the sound’ the Spirit affects in expressions of faith and repentance. Those formerly unwilling to trust Christ now do so freely and willingly.” New birth is, therefore, evidenced in real and tangible ways through faith, repentance, and good works.
As a point of personal application, this means that we can have real and tangible assurance of our salvation when we evidence words and works that are consistent with the kingdom of God rather than the kingdom of Satan. When we look at the Scriptures and see Jesus, do we see merely a man with divine help (like Nicodemus in our text), or do we see the Lamb of God? To see the Lamb of God is evidence of the new birth. It is also an assurance of our salvation. Again, when we look at the world and have compassion on the lost, that is evidence of the new birth and assurance of our salvation because it shows that our hearts are being conformed to the affections of our maker (cf. John 3:16). And again, when we direct the work of our hands to the glory of God in whatever vocation to which he has called us, that is evidence of the new birth and assurance of our salvation because our good works are rightly directed.
 Ferguson, The Holy Spirit, 126  Ferguson, The Holy Spirit, 123