Mat 18:15 Moreover if your brother shall trespass against you, go and tell him his fault between you and him alone: if he shall hear you, you have gained your brother.

This verse raises the who problem with our modern concept of "sin" versus the plain words Matthew uses. What is translated as "trespass" here is the Greek hamartanô. This word and is equivalent, hamartia, are the only words translated as "sin" or "sins" in the Gospels. Neither one means "sin" in the sense we use it. They describe an arrow missing its mark. We would describe the idea as falling short of our goals. The Greek word for sin, alitainô , to "sin" or "to offen," is never used. All the terms that we associate with "sin," such as being a sinner, wickedness, and so on are based on alitainô.

Christ is very clear in this section on what is going on in the world and what goes wrong in the world. We are given freedom. God has a plan for us, a purpose, but we lose our way. We are misled. We stray. This is not caused by wickedness, but by the very fact that we are free. If we could not stray, we wouldn't be free. When we stray, Christ sees it as an error, a mistake. We are falling short of what we could be.

The whole modern sense of religion as a battle between good and evil simply doesn't exists in Christ's words. I have written in detail about how the terms "good" and "evil" themselves are mistranslated.

Alternative: Moreover if your colleague shall err toward you, withdraw and question him between you and him alone: if he shall hear you, you have gained the advantage of a brother.

"Brother" is from adelphos, which means "a son of the same mother," "a kinsman," or "a colleague,"

"Trespass" is from hamartanô, which means "to miss the mark," "to fail in one's purpose," "to err," "to be mistaken," and "to neglect."

"Go" is from hupagô, which means "to lead under," "to bring under," "to lead by degrees," "go away," "withdraw," and "retire."

"Tell him his fault" is from elenchô (elegcho), which "to disgrace," "to put to shame," "to cross-examine," "to question," "to test," "to prove," "to refute," "to put right," "to get the better of," "to expose," and "to decide a dispute."

"Gained" is from kerdainô, which means "to gain," "to gain an advantage," "to derive profit from," and "to save yourself from."