"Anyone who claims to be in the light but hates his brother is still in the darkness. Whoever loves his brother lives in the light, and there is nothing in him to make him stumble.  But whoever hates his brother is in the darkness and walks around in the darkness; he does not know where he is going, because the darkness has blinded him."

• Hatred (love, in fact, seems so strong a 'case' for being a true believer that John writes that there is nothing in such a person to 'make him stumble')

"But you know that he appeared so that he might take away our sins. And in him is no sin. No one who lives in him keeps on sinning. No one who continues to sin has either seen him or known him.  Dear children, do not let anyone lead you astray. He who does what is right is righteous, just as he is righteous. He who does what is sinful is of the devil, because the devil has been sinning from the beginning. The reason the Son of God appeared was to destroy the devil's work. No one who is born of God will continue to sin, because God's seed remains in him; he cannot go on sinning, because he has been born of God. This is how we know who the children of God are and who the children of the devil are: Anyone who does not do what is right is not a child of God; nor is anyone who does not love his brother.


 

• 'Lifestyle' sins or continuous sinning
• Unchanged lives
• Lack of brotherly love

"We know that we have passed from death to life, because we love our brothers. Anyone who does not love remains in death. Anyone who hates his brother is a murderer, and you know that no murderer has eternal life in him."

• Lack of love
• Hatred among Christians
• Murder (presumably not only physical but the kind warned against by Jesus in Matthew 5:21-22, "...anyone who says, 'You fool!' will be in danger of the fire of hell.")

"And this is his command: to believe in the name of his Son, Jesus Christ, and to love one another as he commanded us. Those who obey his commands live in him, and he in them. And this is how we know that he lives in us: We know it by the Spirit he gave us.

• Disobedience and refusal to love

"If anyone says, "I love God," yet hates his brother, he is a liar. For anyone who does not love his brother, whom he has seen, cannot love God, whom he has not seen. And he has given us this command: Whoever loves God must also love his brother."

• Hatred

"If anyone sees his brother commit a sin that does not lead to death, he should pray and God will give him life. I refer to those whose sin does not lead to death. There is a sin that leads to death. I am not saying that he should pray about that.  All wrongdoing is sin, and there is sin that does not lead to death.
 

For our purposes this passage is minimally relevant as it doesn't spell out the nature of the sin which leads to death, even ASSUMING that 'death' in this case refers to spiritual death and that the 'brother' in question is a Christian (John Stott denies that the 'brother' in the passage is a Christian at all given that John admonishes that his readers ask that God gives him life [vs. 16, implying a state of death].  If he's right, then we have nothing here of relevance to intra-community expulsion among Christians).

^"I wrote to the church, but Diotrephes, who loves to be first, will have nothing to do with us. So if I come, I will call attention to what he is doing, gossiping maliciously about us. Not satisfied with that, he refuses to welcome the brothers. He also stops those who want to do so and puts them out of the church. Dear friend, do not imitate what is evil but what is good. Anyone who does what is good is from God."

• Not extending hospitality to fellow Christians
• Gossip
• Pride ("loves to be first") and self-centeredness
• Imitating evil

Bible verse

Cause of Expulsion / Condemnation

"They went out from us, but they did not really belong to us. For if they had belonged to us, they would have remained with us; but their going showed that none of them belonged to us."

• Probably denotes people who never intended to stay in the Christian community

"Who is the liar? It is the man who denies that Jesus is the Christ. Such a man is the antichrist--he denies the Father and the Son. ²³No one who denies the Son has the Father; whoever acknowledges the Son has the Father also...I am writing these things to you about those who are trying to lead you astray."
 

• Specific and active denial of the Messiahship of Jesus Christ (this possibly highlights the specifically Jewish nature of the opponents John had in mind)
• Active intention of leading Christians astray

"This is how you can recognize the Spirit of God: Every spirit that acknowledges that Jesus Christ has come in the flesh is from God, but every spirit that does not acknowledge Jesus is not from God. This is the spirit of the antichrist, which you have heard is coming and even now is already in the world."

• Denying humanity of Jesus
• Denying that the man called Jesus is the Christ

"Anyone who believes in the Son of God has this testimony in his heart. Anyone who does not believe God has made him out to be a liar, because he has not believed the testimony God has given about his Son. And this is the testimony: God has given us eternal life, and this life is in his Son. He who has the Son has life; he who does not have the Son of God does not have life."
 

• Disbelieving that God has given eternal life in His Son

"Many deceivers, who do not acknowledge Jesus Christ as coming in the flesh, have gone out into the world. Any such person is the deceiver and the antichrist. ⁸Watch out that you do not lose what you have worked for, but that you may be rewarded fully. ⁹Anyone who runs ahead and does not continue in the teaching of Christ does not have God; whoever continues in the teaching has both the Father and the Son. If anyone comes to you and does not bring this teaching, do not take him into your house or welcome him. Anyone who welcomes him shares in his wicked work.
 

• Denying humanity of Jesus
• Ignores or disobeys Christ's teaching
• Welcoming teachers who have a deliberate and active intention to deceive