I don't know if there's another passage of Scripture that Christ's followers shy away from as universally as Matthew 5:38-42. Here's the text from the NRSV:
38 ‘You have heard that it was said, “An eye for an eye and a tooth for a tooth.” 39But I say to you, Do not resist an evildoer. But if anyone strikes you on the right cheek, turn the other also; 40and if anyone wants to sue you and take your coat, give your cloak as well; 41and if anyone forces you to go one mile, go also the second mile. 42Give to everyone who begs from you, and do not refuse anyone who wants to borrow from you.
I've heard so much protest about this passage from the everyday Christian to pastors, professors, and even serious scholars who ought to know better. Now, understand I'm not hardly ever a "literal interpretation" kind of person, but this is a direct quote from the Sermon on the Mount which is generally regarded as some of the best stuff Jesus said. Liberal, conservative, and even atheist can read the Sermon on the Mount and respect the teachings, see the beauty of the life Jesus is calling every one of us in the world to live.
Consider the passages surrounding this one: 'love your enemies' comes right after it; immediately preceding is 'yes be yes, no be no'; before that is-
-lust=adultery
-anger=murder
-divorce --> adultery
-The Beatitudes
No one tries to interpret their way out of those. So, why is everyone so quick to rationalize or wriggle or employ some other interpretive gymnastics to get out of this teaching?
Look, I interpret. I have passages I bend over backwards to get around, too. But this is one of the more reliable sayings of Jesus, it's consistent with his other teachings and moreover it is a hallmark of his Way.
I've heard it all, I think. "Well, you can't be a doormat." "The culture dictated that these reactions were demanding equality, a sort of peaceful non-resistance." "Jesus really didn't mean that."
I have to disagree with all of them. I think Jesus meant exactly what it sounds like. I think it's supposed to be hard, taxing, unfair and startling. That's what it means to be salt of the earth and light of the world (also in Matthew 5, btw). We are called to live in such a disturbing manner that it illuminates darkness and leaves a taste on your tongue. Give to everyone, do not refuse anyone.
It's really that simple. I don't live like it, and I still don't want to. But that doesn't change the fact that it's the way I'm called to live.