What is sin?
Sin is anything short of God's perfection. That is what God means when He says that "all have sinned and come short of the glory of God" (Romans 3:23). It is doing what we know we should NOT do -- "All unrighteousness is sin" (1 John 5:17). It is failing to do what we know we should do -- "To him who knows to do good and does not do it, to him it is sin" (James 4:17). It is violating the conscience -- "Whatever is not from faith is sin" (Romans 14:23). It is self-will or lawlessness. It is saying to God, "Not your will but mine be done." Not only are our thoughts, words, and deeds sinful, but our inner lives are sinful. In fact, what we are is a lot worse than anything we have ever done.