Jesus forbids us to judge by appearance (John 7:24). But he is not saying that we are no longer to judge between sin and righteousness. In fact, Matthew 18:15-16 tells us to call our brother’s attention when he sins against you. Not to condemn, but to restore relationship with each other. Even if there is no guarantee that the one who sinned will repent, we should love them enough that we are willing to risk our friendship and talk face-to-face with the offending party.