Focusing on the Christian concept of sin, this chapter explores the way in which Anti-Climacus in Part Two of The Sickness unto Death analyzes the concepts of despair, selfhood, spirit, sin, offense, faith, paradox, and God from the standpoint of a Christian understanding of these concepts in contrast to that of classical paganism and Christendom, especially the way in which these concepts are rooted scripturally in Christianity in not willing or doing what is right rather than not knowing or understanding what one should do, as in paganism. It focuses in particular on the Christian doctrine of hereditary sin and the paradox that sin is not a negation but a position before God that cannot be comprehended but must be believed through a revelation from and relation to God, thereby creating the possibility of offense.

The notion of a specifically Christian moral character receives its normative definition and paradigmatic existential expression in Jesus Christ, who is viewed in the New Testament not only as the redeemer of fallen humanity through his death and atonement but also as the prototype or perfect model of human moral character. Nowhere is the latter character more evident than in the temptation narratives recorded in the synoptic gospels (Mark 1:12–13; Matt. 4:1–11; Luke 4:1–13) and attested by other New Testament writings. According to Mark, the oldest of the synoptic gospels, immediately after Christ's baptism the Spirit descended on him, a heavenly voice declared him to be God's Beloved Son, and he was driven by the Spirit into the wilderness, where he was “tempted” by Satan for a period of forty days. The Greek verb for being tempted (peirasein) in these narratives has two meanings, to test and to seduce or entice, both of which are operative in the synoptic accounts. Although English translations of the New Testament use the term temptation to indicate the enticement of Jesus by Satan or the devil, the temptation of Christ is clearly understood by the New Testament writers as signifying a testing of his perfect obedience and faithfulness to God, in line with a long tradition of testing in the Hebrew Bible. As in the cases of Abraham in the land of Canaan (Gen. 22:1) and the Israelites in the wilderness (Exod. 15:25; 16:4; Deut. 8:2–5), the initiator of Christ's testing in the temptation narratives is God, who puts him to the test through the agency of the figure of Satan. Although Satan is generally viewed in the New Testament as the adversary of God who entices humans to do evil, in this instance he indirectly plays the role of the accuser or heavenly prosecutor, whose primary function, as in the prologue of the Old Testament book of Job (1:1–2:13), is to test the faith and steadfastness of the righteous. Although Mark's account is very brief, merely indicating that Jesus was tempted by Satan, Matthew and Luke identify three specific tests in which the Son of God was tempted to use his divine power for worldly gain, authority, and glory.