Every one of our sinful actions has a suicidal power on the faculties that put that action forth. When you sin with the mind, that sin shrivels the rationality. When you sin with the heart or the emotions, that sin shrivels the emotions. When you sin with the will, that sin destroys and dissolves your willpower and your self-control. Sin is the suicidal action of the self against itself. Sin destroys freedom because sin is an enslaving power.
In other words, sin has a powerful effect in which your own freedom, your freedom to want the good, to will the good, and to think or understand the good, is all being undermined. By sin, you are more and more losing your freedom. Sin undermines your mind, it undermines your emotions, and it undermines your will.
 Available from http://www.desiringgod.org/blog/posts/fighting-sin-with-worship. Excerpt from a sermon available from http://sermons2.redeemer.com/sermons/sin-slavery.