D. M. Lloyd-Jones on sin:
"...it seems to me that one of the main problems in connection with evangelism, especially today, is our failure to realize that sin primarily is disobedience. Sin is not just that which I do that is wrong, and which makes me feel miserable and unhappy; sin is not just that thing which gets me down, and which I would like to overcome. It is all that, but, my friends, that is not the first thing to say about sin; indeed, that is not the most important thing to say about it...What is sin? Sin is the transgression of the law. Primarily, it is rebellion against God."
(Lloyd-Jones, David Martyn. Romans: An Exposition of Chapter 1 ; the Gospel of God. Edinburgh: Banner of Truth Trust, 1985. Print. 138)