Christ Taught About Human Shortfalls Not Sin
Mat 6:14 For if you forgive men their trespasses, your heavenly Father will also forgive you:
Mat 6:15 But if you do not forgive men their trespasses, neither will your Father forgive your trespasses.
Again, today's Christianity emphasizes the idea that Christ taught about sin and forgiveness. This focus makes Christ's role as a redeemer and savior from sin so important. While I don't necessarily argue with the theology here, but Christ's words in the Greek do not seem to support the view, at least as we hear it today. These lines, following immediately after the Lord's Prayer, are a good example.
While these lines in English use the familiar formula of forgiveness and "trespasses," the Greek words used have a very different flavor. First, to give English translations their due, none of them use the term "sin" here for "trespasses." Other terms used are "offenses" or "transgressions." In the original Greek, the term is paraptoma, which literally means "falling beside" (or lying side by side). It is used to mean going off the right path, or, more specifically, stumbling off that path. It is also used to indicate a gramatical mistake. It doesn't mean violating laws or boundaries as you might think from the English words use to translate it. It describes a shortcoming or shortfall (to get to a similar root) than it does sin.
"Sin" in the NT is translated from hamartanô, which means "to miss the mark," "to fail in one's purpose," "to err," "to be mistaken," and "to neglect."
In Greek, the word not used in the Bible, the word that precisely means "sins" is alitros, which means "sins," "sinner," and "sinful." It is impossible that the authors of the NT didn't know this word. All other Greek words based on the idea of sin are relate to it--alitria (sinfulness), alitêrios (sinning), aleitês (sinner) and even, this is funny, alêtheia (sincerity).
There is a similar problem with the word translated as "forgive." The NT authors use Greek word is aphiemi, which is an extremely common word in Greek (unlike many of the key words used to capture Christ's words). Aphiemi does not mean forgive or anything like it. Greek has a dozen words for "forgive" including didomi, a word Matthew has used before to mean "giving to God." Aphiemi means to send forth, discharge, to divorce, get rid of, and so on.
So Christ is not talking about forgiving sins here, even though that is the way we might hear these verses preached in most churches. He is teaching us not to shun or send away those who fall short because God does not send us away when we fall short. When people fall by the way (which to my mind doesn't bring to mind evil people as much as it does alcoholics, drug addicts, and people like that), we shouldn't turn our backs on them.
Modern Christianity teaches loving the sinner while hating the sin, which is very close to this idea. However, in practical terms, Christianity has often excluded those who fell short from the community. Would the Puritans have practiced shunning if they read the Bible in the original Greek instead of English translation?
Again, the larger lesson here is that we are on earth to perfect ourselves. We perfect ourselves by emulating God. We treat others, not just as we would have them treat us, but as God treats us. In our personal practices, we leave it for God to judge others, which--in this life at least--he seems to do very generously.