Are you violating Matthew 18 if you publicly disagree with a fellow Christian? For example, if you are referencing a book that you disagree with?
Matthew 18 says “If your brother sins against you, go and tell him his fault, between you and him alone.” If someone disagrees with something I’ve written, I certainly don’t view him as having sinned against me. Does the person with the opposing view think that I have sinned against him? If so, then we would definitely need to talk.
My belief is that whenever a book is published, the author is going public. He need not run his book by everyone who might disagree with it, and those who disagree with it do not need to run their thoughts by him. No one has to contact me personally before disagreeing with what I have publically stated about Heaven, abortion, civil disobedience, or a hundred other subjects. People constantly disagree with my conclusions by the dozens, and I take no offense that they haven’t tried to meet with me personally. Disagreement or differing perspectives are not the same as committing sins against a brother. I think disagreement should be cautious and civil. But if the other brother is offended, by all means let’s discuss it.