Repent or Perish.
This is a hard teaching of Christ. It is unrelenting and direct in it's objective; but – as are all things with Christ – it is rooted in unconditional love. The word that Christ would have used to say "repent" is the word "Metanoia". While the concept of repentance has been distorted and perverted into meaning to simply stop sinning, the word that Christ used is a word that means "to think differently". God's heart is not focused solely on our actions, but rather, on our motivations. Therefore, His charge to those that follow Him is not to resist the urge to act negatively. It is to seize the opportunity to act positively.
Lyrics taken from http://www.lyricsmode.com/lyrics/f/for_today/immanuel_the_challenger_lyrics.html