How does it happen that some people do not believe the gospel when they hear it but others come to faith in Christ and find their redemption in him? How is it that for some the gospel is the aroma of death and for others it is the aroma of life? Herman Bavinck answers these questions well using Scripture:
“The cause of that, according to the teaching of Scripture, cannot lie within the individual. For by nature all people are alike. They are all born in unrighteousness and sin their mothers conceived them. The imagination of their hearts is evil from their youth, such that out of the heart proceed all manner of wicked thoughts and iniquities. Their understanding is darkened, so that they cannot see the kingdom of God and cannot understand the things of the Spirit of God. The thoughts of their flesh are enmity against God…all of them are bondservants to sin. …Of themselves they can neither think anything good nor do anything good – something as impossible as an Ethiopian changing his skin or a leopard its spots, or a bad tree producing good fruit” (p. 28).
What then is the cause of faith, or how does a person dead in sin come to faith? Bavinck says that God is the one who makes the distinction “according to his good pleasure.” By his Spirit, God penetrates dead hearts and renews them; he opens the closed heart and breathes new life in the chambers of the dark heart (cf. Deut. 20:6; Ps. 51:12; Jer. 24:7; 31:33; 32:39-40; Ezek. 11:19; 36:26, etc.).
“God is the primary actor in the work of regeneration. He gives a new heart, apart from any merit or condition having been achieved from our side, merely and only according to his good pleasure. He enlightens the understanding, bends the will, governs the impulses, regenerates, awakens, vivifies, and he does that within us quite apart from our doing. From our side there is nothing between this operation of God’s Spirit within our hearts and the fruit thereof, which is termed ‘regeneration’ in a narrow sense, or new creation, resurrection, vivification. No consent of our intellect, no decision of our will, no desire of our heart comes in between. God accomplishes this work within our hearts through his Spirit, and he does this directly, internally, and invincibly” (p. 29).
In other words, regeneration is monergistic: God alone does the work. The Canons of Dort say that the Holy Spirit “opens the closed and softens the hardened heart, and circumcised that which was uncircumcised…” (CoD III/IV.11). The Westminster Confession describes this effectual call as being “of God’s free and special grace alone, not from anything at all foreseen in man, who is altogether passive therein” (10.2). Indeed, salvation belongs to the Lord and he alone receives the glory for every part of it!
The above quotes are found in Herman Bavinck’s Saved By Grace: The Holy Spirit’s Work in Calling and Regeneration.