What is good, right, and virtuous is grounded in the triune God of the Bible. God isn't morally moody. Given this eternal anchorage for ethics, sin must be seen as the transgression of God's law. Sin is an offense against God, ourselves, and others. In the modern Western world, ethical relativism poses a challenge to the biblical basis for ethics.
Relativism affirms that moral right and wrong are only socially and individually determined.
Ethics is split off from any objective moral order. Cultural norms of morality are relative to particular societies, individuals, and historical periods. What is wrong today may not be wrong tomorrow. When the idea of moral law is held in disrespect, the notion of sin softens and then dissolves. If all is relative, absolute evil is impossible.