The Bible makes it clear that man is not merely impaired, but dead in trespasses and sins (Eph. 2:1-3). Regeneration involves a new heart and a new spirit-the natural man, being spiritually dead, cannot produce this new birth in himself. Van Mastricht says, "If man were, either in whole or in part, the author of his own regeneration, he would enable himself to differ, contrary to the apostle's assertion (1 Cor. 4:7)."
Man is passive in regeneration; he is born of the Spirit (John 3:5-6), born of God, and not born of anything in, not his blood, his flesh, or his will (John 1:13). Regeneration must be the sovereign work of God the Holy Spirit. There is no cooperation or synergism when it comes to regeneration. Man is not born of the Spirit and of his own will. The new birth is monergistic, not synergistic. New birth is an "effect or work of the Spirit in us" and not a "begetting of a nature or being, the same that the Spirit himself is of." The Spirit of God is the "efficient" cause or the "principal, the sole author" of regeneration. In this work we have no part. The believer can concur with the Spirit in his sanctification, says John Flavel (1628-1691), "but in the first production of this spiritual principle he can do nothing." Furthermore, if human nature could concur in regeneration, then "the best natures would be soonest quickened," but we more often see the worst of men regenerated. In regeneration, man does not "contribute toward this work" because it is the sovereign and supernatural work of God. The Spirit is the "efficient principal of it." In saying this, they were saying that in regeneration, divine grace reigns and human nature is passive. Grace works on nature to give it life; nature cannot and does not cooperate with grace. . ." pg. 469,470 A PURITAN THEOLOGY by Joel R. Beeke & Mark Jones
" Therefore seeing we have this ministry, as we have received mercy, we faint not;
 But have renounced the hidden things of dishonesty, not walking in craftiness, nor handling the word of God deceitfully; but by manifestation of the truth commending ourselves to every man's conscience in the sight of God.
 But if our gospel be hid, it is hid to them that are lost:
 In whom the god of this world hath blinded the minds of them which believe not, lest the light of the glorious gospel of Christ, who is the image of God, should shine unto them.
 For we preach not ourselves, but Christ Jesus the Lord; and ourselves your servants for Jesus' sake.
 For God, who commanded the light to shine out of darkness, hath shined in our hearts, to give the light of the knowledge of the glory of God in the face of Jesus Christ.
 But we have this treasure in earthen vessels, that the excellency of the power may be of God, and not of us." 2 Corinth. 4:1-7