Augustine defends the claim that sinless human life is theoretically possible through God’s grace, even though no ordinary person has achieved it. Human free will and effort are insufficient: the law reveals sin and may intensify transgression when obeyed only from fear, while the Holy Spirit heals the will, pours love into the heart, and enables genuine obedience. The “letter” written on stone thus kills when treated as an external command, whereas the “spirit” of the New Covenant gives life by writing God’s law inwardly. Against boasting in works, Augustine presents righteousness and justification as gifts through faith in Christ. The law of faith excludes human merit, and the promise to Jews and Gentiles is fulfilled as grace makes them “doers of the law.” He distinguishes natural moral awareness from the renewing grace of the Spirit, which restores wounded human nature and makes true righteousness possible. Grace does not abolish freedom but establishes it, while faith remains a voluntary response to God’s initiative. Baptism forgives, faith and love heal, and resurrection completes the process in the vision of God; present believers possess only an inferior righteousness and partial knowledge while awaiting perfection.