In Christianity, salvation (also called deliverance or redemption) is the saving of human beings from sin and its consequences—which include death and separation from God—by Christ's death and resurrection, and the justification entailed by this salvation.
The idea of Jesus' death as an atonement for human sin was recorded in the Christian Bible, and was elaborated in Paul's epistles and in the Gospels. Paul saw the faithful redeemed by participation in Jesus' death and rising. Early Christians regarded themselves as partaking in a new covenant with God, open to both Jews and Gentiles, through the sacrificial death and subsequent exaltation of Jesus Christ.
Early Christian beliefs of the person and sacrificial role of Jesus in human salvation were further elaborated by the Church Fathers, medieval writers and modern scholars in various atonement theories, such as the ransom theory, Christus Victor theory, recapitulation theory, satisfaction theory, penal substitution theory and moral influence theory.
Variant views on salvation (soteriology) are among the main fault lines dividing the various Christian denominations, including conflicting definitions of sin and depravity (the sinful nature of mankind), justification (God's means of removing the consequences of sin), and atonement (the forgiving or pardoning of sin through the suffering, death and resurrection of Jesus).
Definition and scope
Salvation in Christianity, or deliverance or redemption, is the "saving [of] human beings from death and separation from God" by Christ's death and resurrection.
Christian salvation not only concerns the atonement itself, but also the question of how one partakes of this salvation, by faith, baptism, or obedience; and the question of whether this salvation is individual or universal. It further involves questions regarding the afterlife, e.g. "heaven, hell, purgatory, soul sleep, and annihilation." The fault lines between the various denominations include conflicting definitions of sin, justification, and atonement.
Sin
In the West (differentiating from Eastern Orthodoxy) Christian hamartiology describes sin as an act of offence against God by despising his persons and Christian biblical law, and by injuring others. It is an evil human act, which violates the rational nature of man, as well as God's nature and his eternal law. According to the classical definition of Augustine of Hippo, sin is "a word, deed, or desire in opposition to the eternal law of God".
Christian tradition has explained sin as a fundamental aspect of human existence, brought about by original sin—also called ancestral sin, the fall of man stemming from Adam's rebellion in Eden by eating the forbidden fruit from the tree of knowledge of good and evil. Paul espouses it in Romans 5:12–19, and Augustine of Hippo popularized his interpretation of it in the West, developing it into a notion of "hereditary sin," arguing that God holds all the descendants of Adam and Eve accountable for Adam's sin of rebellion, and as such all people deserve God's wrath and condemnation—apart from any actual sins they personally commit.
Total depravity (also called "radical corruption" or "pervasive depravity") is a Protestant theological doctrine derived from the concept of original sin. It is the teaching that, as a consequence of the fall of man, every person born into the world is enslaved to the service of sin as a result of their inherent fallen nature and, apart from the irresistible or prevenient grace of God, is utterly unable to choose to follow God, refrain from evil, or accept the gift of salvation as it is offered. It is advocated to various degrees by many Protestant confessions of faith and catechisms, including those of some Lutheran synods, and Calvinism, teaching irresistible grace. Arminians, such as Methodists, also believe and teach total depravity, but with the distinct difference of teaching prevenient grace.
Justification
In Christian theology, justification is God's act of removing the guilt and penalty of sin while at the same time making a sinner righteous through Christ's atoning sacrifice. The means of justification is an area of significant difference among Catholicism, Orthodoxy, and Protestantism. Justification is often seen as being the theological fault line that divided Catholic from the Lutheran and Reformed traditions of Protestantism during the Reformation.
Broadly speaking, Eastern Orthodox and Catholic Christians distinguish between initial justification, which in their view ordinarily occurs at baptism; and final salvation, accomplished after a lifetime of striving to do God's will (theosis or divinization).