The doctrine of sin is one of the most fundamental doctrines of the Christian faith. A correct understanding and interpretation of this doctrine is crucial, for if one desires to have a sound system of theology they must be able to rightly understand sin and its effects on the human race. Sadly many Christians today seem to have a flawed understanding of sin due to its unpopularity in our modern society. Many people in and out of the Christian faith have no desire to be confronted with the subject of sin because of its personal and probing nature. As a result of this attitude the doctrine has all but been forgotten, replaced with the more palatable and popular teachings of the “health and wealth” or “best life now” versions of the gospel.
A refusal to understand sin and its consequences, however, does nothing to change the fact that Scripture overwhelmingly declares man to be a sinful creature deserving of God’s wrath. Like it or not, people need to be reminded of the nature of sin and confronted with sound biblical teaching on the subject. In order to better understand this doctrine one must seek to study both Scripture and Church history as it pertains to what others have believed and taught about sin throughout the centuries.
Main Beliefs Concerning the Doctrine of Sin
Many beliefs have been held about the doctrine of sin throughout the history of the Christian faith. One could write volumes on the different theories and explanations that have been given to best describe human sinfulness and the imputation of sin to man. A great number of these theories have had a lasting impact on the faith and are still extremely influential on theologians today. Due to the brevity of this post, however, only a brief overview of these theories can be discussed. As a result, special emphasis will only be given to those who have been most influential in developing this doctrine.
Early Church father Augustine of Hippo had a profound influence on the Christian faith with his doctrine of original sin. Prior to Augustine, no other theologian had developed such a strong concept that so closely related the sin of all of humanity with the sin of Adam. Augustine championed what has been dubbed “natural” or “seminal” headship, a theory that states that all humans were physically, or seminally, present in Adam. Thus, according to Augustine, every human being can be charged with the guilt of Adam because they were “present” with him when he sinned in the garden. The primary text Augustine used to build his doctrine of sin was Romans 5:12, a verse he claimed as proof that all people shared in the actual commission and guilt of the original sin of Adam. Augustine also used Psalm 51:10 to defend his argument that all infants were guilty before God of original sin and condemned to hell, thus necessitating the need for remission of sin through infant baptismal regeneration. 
The influence of Augustine can clearly be seen in the teachings of both Martin Luther and John Calvin. Both of these men held to strict views of original sin and depravity. Luther believed that the fall resulted in the reception of natural sin by all humans from their parents in their mother’s womb. Calvin believed that Adam acted as mankind’s “federal head” or representative in the garden. When Adam fell, according to Calvin, he failed the human race and brought both the curse of death and the guilt of original sin on all of his descendants. This is known as the theory of federal headship, a view widely held today among many Calvinistic theologians. 
In direct opposition to the Augustinian and Calvinistic views, however, theologians such as E. Y. Mullins, W. T. Conner, Dale Moody, and Millard J. Erickson have all rejected the corporate ideas of inherited sin and guilt and have argued for views that stress guilt for individual sins. For instance, Mullins rejected Federal Headship on the claim that it could not be adequately supported by Scripture. He argued that instead of inheriting actual sin from Adam, man inherits a tendency to sin that will eventually manifest itself once a person is capable of moral understanding. Conner, Moody, and Erickson all held similar beliefs. This line of argumentation allows for humans to be condemned for their own sin, not Adam’s. 
Correct Biblical Teachings that Support the Doctrine of Sin
The Bible is clear that sin is a real and present stain upon all of creation. The consequences of sin are drastic; death, unrighteousness, spiritual deadness, separation from God, and ultimately the death of Christ are all related to this horrific problem (Gen. 3:15-24; 6:5; Rom. 1:18-32; 3:9-18, 5:12, 6:23; 7:9; John 3:16). There is no doubt; sin is an ugly reality, especially as seen through the eyes of a holy and righteous God.
When describing its nature, Scripture describes two types of sin: sins of commission and sins of omission. Sins of commission deal with a person doing what they should not do (1 John 3:4). Sins of omission, on the other hand, involve a person not doing what they should do (James 4:17). The chief terms throughout the Bible in reference to sin include: trespass (Num. 31:16); iniquity (Isa. 53:11); evil (Matt. 7:11; Rom. 7:21); and wickedness (Ps. 1:1; Matt. 23:28; 24:12; Rom. 6:19; 2 Cor. 6:14). The Bible also declares that sin can manifest itself in numerous ways. One example can be found in Galatians 5:19-21. There Paul list acts of a sinful nature: impurity and debauchery; idolatry and witchcraft; hatred, discord, jealousy, fits of rage, selfish ambition, dissensions, factions and envy; drunkenness, and orgies. 
The Bible also describes the extensive effects of sin on both the human race and on individuals (Rom. 3:23). The fall of Adam has ultimately resulted in the fall of the entire human race. As a result, mankind is irredeemable, except by the grace of God in Christ Jesus (Titus 3:5-7; Eph. 2:8-9).  The fall has also resulted in the depravity of mankind. Depravity, as defined by theologian Henry C. Thiessen, is “man’s want of original righteousness and of holy affections toward God, and the corruption of his moral nature and his bias toward evil.”  While this depravity extends to every part of a human being, it is not exhaustive. In other words, it does not destroy ones humanness; if it did, one would not be able to think, feel, or choose and would thus be incapable of sinning. 
Finally, the Bible describes the defeat of sin. As theologian and apologist Norman Geisler has said, “God chose not to annihilate sin but rather defeat it.”  God premeditated from eternity past His perfect and divine plan to defeat evil, ultimately culminating in His Son, Jesus Christ. God prepared Him as the Savior to bring salvation to everyone who would believe in Him for forgiveness of their sin. Christ came as God incarnate (John 1:1, 14), lived a perfect and sinless life (Heb. 4:15), died a substitutionary death on the cross (John 10:15), physically resurrected from the dead (Mark 16:6), ascended in body into heaven (Acts 1:9-11), and will one day return to judge and reign as the True King of all (Rev. 20:4; 7-15).  Again, Norman Geisler has said, “While the serpent bit the Savior’s heel, Christ crushed the devil’s head. The defeat of sin has not been swift and immediate, but it will be complete and final.” 
The Current Implications of the Doctrine of Sin as it Relates to Ministry Today
Because the doctrine of sin is vitally important to the Christian faith, the local church must have ministries of repentance and reconciliation. The mission of the church can be found in the words of Christ in Matthew 28:19-20: “Go therefore and make disciples of all the nations, baptizing them in the name of the Father and the Son and the Holy Spirit, teaching them to observe all that I commanded you; and lo, I am with you always, even to the end of the age (NASB).” In order for disciples to be made the church must preach to all people the message of repentance for the forgiveness of sins in the name of Jesus (Luke 24:47). The preaching that all people must repent is a bold declaration that they are to abandon their life of sin and turn from their false idols. The message of reconciliation, however, is the good news that God is ready and willing to forgive anyone who is truly repentant and bring them into a relationship with Himself through His Son, Christ Jesus. 
Repentance and reconciliation are at the core of the gospel message because people are sinful and in need of a Savior to rescue them from their sin. The declaration of the gospel is that God has made atonement for the sin of the entire world in Christ Jesus. This is why the doctrine of sin is so vitally important to the Christian faith. Without this doctrine people would never know their true condition or appreciate the sacrifice God has made for them in Christ. 
 R. Stanton Norman, “Human Sinfulness,” in A Theology for the Church, ed. Daniel L. Akin (Nashville: B & H Publishing Group, 2007), 438-439.
 Norman, 438-439.
 Ibid., 445-449.
 Norman L. Geisler, Systematic Theology in One Volume (Minneapolis: Bethany House, 2011), 756-759.
 Geisler, 789.
 Henry Clarence Thiessen. Lectures in Systematic Theology, Revised Paperback ed. (Grand Rapids: William B. Eerdmans Publishing Company, 2006), 191.
 Geisler, 767.
 Ibid., 790.
 Ibid., 800-804.
 Ibid., 810.
 Norman, 477.
 Ibid., 477.