What is it that is effected and brought forth by the regenerative activity of God in the human heart? Scripture describes this product of the re-creating grace of God with various words and images. It describes it as a circumcised heart (Deut. 30:6; Rom. 2:29), a pure heart and a firm spirit (Ps. 51:17), a heart of flesh instead of a heart of stone (Jer. 31:33ff.; Ezek. 11:19; 36:25), a new creation (2 Cor. 5:17), God’s workmanship (Rom. 14:20; Eph. 2:10), a new self (Eph. 4:24; Col. 3:10 NRSV), a new life (Rom. 6:11; Eph. 2:5; Col. 3:3), and so forth. … Humans, who originally were the image of God, lived and experienced blessedness in communion with God, lost that life, and were subject in soul and body to corruption. Sin began with an act but penetrated the very nature of humans and corrupted them totally. It may not be a substance, but it is not merely an act either. It is an inner moral corruption of the whole person, not only of one’s thoughts, words, and deeds but also of one’s intellect and will; and again not only of these faculties but also of the human heart, from which all iniquities flow, of the central inner core, the root of one’s existence, the human self. And for that reason, according to Scripture, regeneration consists and can exist in nothing less than the total renewal and re-creation of human beings. If humans are radically evil, then, for their redemption, a rebirth of their entire being is indispensable. A tree must first be made good if it is ever to bear good fruit, for “functioning follows being.”
Source: Herman Bavinck, Volume 4. Holy Spirit, Church and New Creation, Part I The Spirit gives New Life to Believers Chapter 1 Calling and Regeneration ‘Becoming Spiritual Persons’
Andrew Groves 