Most people interpret this as Jesus way of telling us sin must be avoided at ALL costs. But I tend to agree with Dallas Willard’s interpretation.
When you put this in the context of the entire Sermon, it seems likely that Jesus was saying something like this: “If you think sin is nothing more than wrong action … then why don’t you just eliminate the body part that is sinning?”
This is actually the basis of Law in some cultures … where the punishment for theft is to cut off a hand. In some countries, women … by law … must be covered head to toe in a Chador … a long, thick, dark, loose robe with a veil over the face and a slit to look through.
This rule came about in a misguided attempt to avoid all possibility of lust. After all, how can a man have lustful thoughts if he has nothing to look at? Historically, such a solution regards the woman as the problem. Some men have even been known to cultivate hatred of women in order to avoid lusting for them. Is that Right Living? Is that the way of The Kingdom of Jesus?