What is Sin?
Sin, by definition in the Bible, is not wronging another person.
It is assaulting the glory of God, rebelling against God.
Sin, by definition, is a vertical phenomenon, a vertical dimension. It is disobeying God's law. It is an assault on God's authority and his right to tell you what to do.
What makes sin sin is its Godwardness. That's why the world doesn't understand how serious hell is, because they don't understand how serious sin is. And they don't understand how serious sin is because the only way the world thinks about sin is in terms of "You hurt me and I hurt you, and that shouldn't be."
It's true that we shouldn't hurt each other. But when we don't bring God into the picture when we are hurting each other, that's where we have committed a sin.
[John Piper]
