Perhaps this would be as good time as any to remind ourselves that only God may pass spiritual judgement and, that when Man thinks himself entitled to judge his brother, he himself is most likely committing a sin.
Humbly
Hermit
The main problem interpreting the word "judging" is causing true believers in the God committing sin when accepting the bad doings of sinners.
Take it this way. If you see your neighbor stealing, cheating on the spouse, being a homosexual, you can talk to him or her, and call him/her to repentance.
You can rebuke, reproach, repress, denounce, excoriate, objurgate him/her when you find a member of your assembly doing wrong.
Yes, feel free of doing it, tell them the plain truth, their souls and body will die, no exceptions.
Why you can do it freely without hesitation?
Because you are not condemning them. You are not giving them sentence to die or forgiveness or punishment.
You are just telling they are wrong and better for them to change, and such is not judging.
So, don't think you are doing wrong when you reprimand others because their bad actions, because Yeshu (Jesus) and the apostles did it, so you better do the same.
If you keep silence, you are the one who is going to be in trouble with the God, because He told you to spread His word and you have betrayed Him by keeping your mouth shout.
When is about the recognition of the messiah, denying him means for the apostle to be a lie.
I kind to disagree with that statement when the denial comes from a person who is not a believer of the God of the Bible and that Yeshu (Jesus) His son.
People who don't belong to Christian churches have the right of opinion. The words of the apostle appear to be send to members of the churches, whom at one moment disagree for some reason with the main point of the good news.