This fact, that the opposite of sin is by no means virtue, has been overlooked. The latter is partly a pagan view, which is content with a merely human standard, and which for that very reason does not know what sin is, that all sin is before God. No, the opposite of sin is faith.
"The Sickness unto Death". Book by Soren Kierkegaard, Part Two: Despair Is Sin, pp. 114 - 115, 1849.