Piper is in Cambridge at the moment on sabattical - just a few miles away from my house. He has an interesting post entitled
How to Respond to Horrifying Sayings of Jesus:

"One of the things I am doing at this point in my sabbatical here in Cambridge, England, is reading through the four Gospels and collecting all the explicit and implicit commands of Jesus into various categories. I am driven in this endeavor by Matthew 28:18-20. Jesus said, �All authority in heaven and on earth has been given to me. Go therefore and . . . [teach all the nations] to observe all that I have commanded you.� So it is important that we are able to do that. We should teach and obey �all that he commanded us� because he has �all authority� in the universe. No one else has the right, the wisdom, or the love to tell us how to live. Only Jesus has that authority.

But when you read through the Gospels you find some horrifying things. If you don�t feel them as horrifying, you are not awake. I think they are calculated to wake us up form our domestication of Christ and his book...

Piper goes onto describe a parable that demonstrates the righteous anger of Christ towards sinners and among his lesons learnt says

"We feel pricked in conscience that there is too often a self-righteous contempt for rebellious people that rises in our hearts�and we add that sin to all the rest that make us good candidates to be slaughtered along with the rebellious."

The Christian should never be so complacent in their knowledge of Christs love and forgiveness that they forget the sin that puts us in need of his forgiveness. No sin is more heinious than our tendency to hate and have contempt for the sinners who due to their blindness continue to rebell as we once did. Christians should not be condemning of others- we should rather be like a beggar who has found bread and no wants to share that bread with the other beggars.