If another believer sins against you, go privately and point out the offense. If the other person listens and confesses it, you have won that person back.
This is how we know if they have the Spirit of God: If a person claiming to be a prophet acknowledges that Jesus Christ came in a real body, that person has the Spirit of God. But if someone claims to be a prophet and does not acknowledge the truth about Jesus, that person is not from God. Such a person has the spirit of the Antichrist, which you heard is coming into the world and indeed is already here.
I have told you all this so that you may have peace in me. Here on earth you will have many trials and sorrows. But take heart, because I have overcome the world.