Below is an excerpt from a recent Joshua Harris's blogpost.
I've been enjoying Tullian Tchividjian's forthcoming book Jesus + Nothing = Everything. Here's a great quote from a chapter on the dangers of legalism, or what Tullian likes to call "performancism."
"Legalism traps you in slavery and despair. To define ourselves by what we must do, what we must accomplish, and who we must become--that's the epitome of slavery. When we believe, deep down, that God's blessing depends on how well we're behaving, we wither and groan under the heavy burden of self-reliance.
http://www.joshharris.com/