Ryrie discusses the fruits of regeneration:
“The new birth brings a new nature (2 Corinthians 5:17). It does not eradicate the old (better texts do not say ‘all things are become new,’ but ‘new things have come’), nor does it split the personality. Natures are capacities, and whereas the unregenerate person has only the capacity to serve sin (Romans 6:20), the regenerate person has a new nature with its capacity to serve righteousness (Romans 6:18). The Holy Spirit is also involved in the life and activity of the new creation, controlling and filling (Romans 8:4, 14; Galatians 5:16; Ephesians 5:18). The believer is not made perfect, but he does have the new capacity to please God and to grow into the image of Christ because of the new birth and the subsequent ministries of the Spirit in his life.”
I offer in clarification that the “new nature” that is mentioned by Ryrie refers to the human soul, consisting of mind, will and emotion. When regenerated a person has a new mind that wills to please God (Ezekiel 36:26), bringing joy to the believer. It is a process that occurs through sanctification so that the person becomes over time more Christlike. The Holy Spirit serves as Counselor and Helper.