Modern theologians, political theorists, and academics have distanced themselves from discussing evil and sin as a part of the human condition. However, the Bible, Christian thinkers, and historical political theorists have often included the idea that man has a sinful nature. This theo-centric anthropology looks at man as one born with the desire to sin and that it is necessary for God to reform people. Although God created man perfectly, original sin tainted human nature and morphed it into something evil rather than good. Subsequently, ideas on how to limit and change this sinful nature has dominated Christian thought. Without the basis of a sinful nature, Christian thought makes little sense. Jesus and the writers of the New Testament consistently discussed transforming man from being sinful into being holy. It is important to maintain an understanding of man’s fallen nature because it is the basis of Christian ethics and the self.

The opening chapters of Genesis explain how God created man and woman, and how they both sinned against God, the Original Sin. Genesis 3, the story of the Fall, has three primary lessons to teach believers about the Biblical notion of human nature. The Christian notion on the doctrine of Original Sin has two key elements. First, Adam and Eve went against the will of God and brought sin into the world. Second, their actions fundamentally altered human nature until the eschaton and the resurrection of people’s new bodies. St. Augustine of Hippo called this new nature libido dominandi, the lust to dominate. What does this mean? It means people are now, post-fall, selfish and prideful by nature. This is no longer a nature that craves communion with God; instead they have proclivities towards sin and iniquities.

Paul of Tarsus first put forward these thoughts in his Epistle to the Romans, which inspired St. Augustine’s thoughts on the topic. Paul wrote, “[J]ust as through one transgression condemnation came upon all, so through one righteous act acquittal and life came to all. For just as through the disobedience of one person the many were made sinner, so through the obedience of one the many will be made righteous” (Romans 5:18-19). His understanding of human nature was that Adam had brought sin into the world, and because this sinful nature even a man as pious as himself committed sins against God that he did not want to do. The imminent 20th century theologian Reinhold Niebuhr offers a similar explanation for a Biblical view of man. He discusses the paradoxical relationship of men to God in their desire to be in His will and the fact that men are sinners. “The Christian estimate of human evil is so serious precisely because it places evil at the very center of human personality: in the will.” The predominant Christian thought is that man has a sinful nature, and it is this nature that leads him to go against the will of God.

Many of the books of the New Testament deal with how Christians should behave as individuals to limit their sinful nature. There are many dictums on transforming the inner soul and what this will mean for the believers’ actions to themselves and others. H. Richard Niebuhr describes how God’s “work is concerned not with the specious, external aspects of human  behavior in the first place, but that he tries the hearts and judges the subconscious life; that he deals with what is deepest and most fundamental in man.” The Gospel of John exemplifies this thought best when he shifts the focus from the parousia, the return of Christ, to the coming of the Paraclete, the Holy Spirit, that will allow the believer to commune with God in this life time. Christ will send the Paraclete, and the Third Person of the Trinity will transform man and woman from the inside (John 16:7-11). God essentially is untwisting what original sin twisted in the first place; He is undoing evil in man and stopping his “lust to dominate” nature.

Niebuhr further stated that the “Christian life consists…in the transformation of all actions by Christ, so that they are acts of love to God and man….” In the Sermon on the Mount, Jesus systematically delineates this message by moving away from the previous Judaic concept of regulation of behavior to changing the inside of man (Matthew 5-7). He argues that sin is not merely the action of killing someone or committing adultery, but sin is also the very thoughts someone has. The Christian ethics of the self is about transforming and radically altering man’s sinful nature. Jesus implored his followers to turn away from what was inside of them and undo the evil in their hearts. Without the theo-centric anthropology of man’s fallen nature, these concepts have no meaning. God radically changes believers’ lives by altering the effects of original sin.

The Biblical notion of man is not one offers the idea of inherent goodness and charity. Rather, the Bible describes how original sin tainted humanity and now people are sinful by nature and dominated by evil desires. Jesus, Paul, St. Augustine, and others taught that although man had a sinful nature, people could be transformed by the power of God and limit their evil desires. The base of Christian ethics is the idea that man is sinful, which is why Jesus and his followers discussed how to bind this nature so that the self, the state, and warfare were not unlimited and unchecked. John the Beloved contended that God offered the Holy Spirit to change men so that they would turn towards Him rather than sin. Looking at Christian thought and history the theo-centric anthropological idea that man has a fallen, sinful nature becomes quintessential. Theologians and modern thinkers need to maintain sin, evil, and fallen nature in their way of thinking, because Christian ethics is absolutely dependent upon them.