After looking at Revelation 17 and considering all the ways the world deceives us, I feel it best to look at 2 John and false teachings

In these verses, John explains why he's writing his second letter. He's addressing a woman, referred to as the “chosen lady,” known for her hospitality and generosity towards traveling preachers.

In those times, there weren't many hotels, so people relied on such individuals to open their homes to them. However, alongside genuine preachers, there were also deceptive ones who took advantage of kind-hearted people like her. John warns against supporting false teachers, emphasizing that it's harmful to the cause of truth. 

This warning isn't just for his time; it's relevant across generations, as false teachers continue to pose a threat, with an even larger platform today. John's message resonates with us today, reminding us to be discerning and not to support those who oppose the truth of God's Word.

The devil is always trying to infiltrate the church. The greatest threat to the church is not what's taking place outside the church—it's what's taking place inside the church. Satan is the one who has invaded the church and is on the inside. He has access to the pulpit and to the spiritual life of the church. 

The devil is always trying to join the church. He'll come through the front door, he'll come through the back door, or he'll come through the side windows. Like a Trojan horse, however he can get into the infrastructure of the church, he will try to do so.

That's what John is addressing here at the beginning of 2 John 10: "if anyone comes to you." 

“Anyone” here refers to the false teacher who doesn’t hold to the teaching of Christ. No matter how:

—winsome their personality is, 

—engaging their delivery is, 

—good their people skills are, 

—attractive their appearance, 

—religious-sounding they are,

—many verses they can quote…

In other words: if someone like that comes to you, they are, really, wolves in sheep's clothing. Their goal is to approach you and work their way into your confidence and establish a base of operation. Tthey will tag team on your network of relationships, and your friends will become their friends.

Note: The "you" here refers to the “chosen lady” of 2 John 1, who is a true believer. She doesn’t bring this teaching. No, it is the person who comes and doesn’t bring this teaching

What kind of teaching are we talking about? The word for “teaching” is a Greek word that means doctrine - sound doctrine. So this false doesn't bring the proper teaching of 2 John 1. John describes it as truth (v. 2, 3) and teaching (v. 9)

The gold standard is the truth—it's sound doctrine (Titus 2:1). It is what Jude 3 calls the faith “once and for all delivered to the saints.” “The faith” with a definite article—the objective content of the faith, the Christian faith. 

—In Rom. 6:17, it's that form of teaching to which you were committed. 

—In Acts 2:42, it's the apostles' teaching. 

Just remember: truth means reality. It means the way things really are. And the way things really are is what God says things are in his Word. 

Truth isn’t: 

—What a group of people say it is, 

—What the culture says it is,

—What the majority of people say something is.

Truth is whatever God says something is and is what is recorded in his Word. 

Truth is so invaluable that:  

—If you're trying to get to Christ—to know him in a personal relationship, to be saved, and to be converted— you cannot be converted without the truth.

— If you're trying to discern God's will for your life, you cannot find it apart from the truth. 

—If you're trying to grow as a Christian… 

—Iif you're trying to know how to raise your children…

—If you're trying to know how to conduct yourself….

You cannot do it apart from the truth. You cannot get there without the truth. 

In short, if the truth is ever marginalized or compromised, then you're in a massive amount of trouble. 

And so, there were these false teachers in John’s letter who are bringing what is contrary to the truth. It's no small matter. Friends, false teachers are the most dangerous people on the planet.  

It's like the fisherman who puts a worm on the hook. The fish can't see the hook. If he could see the hook, he wouldn't go for it. But the worm is the deception to lure in the fish, to chomp at the worm, and they get more than the worm. Now they're caught. 

And that's what the false teachers do: They have just enough truth covered with a lie. Or, better said, they have a lie covered with some of the truth to bait you and to lure you in. They're on television, radio, internet, podcasts, books, and just about everywhere, it seems. And they use the name “Jesus,” they talk about heaven, and they talk about life. They have just enough of the worm that you bite the damnable lie that they “teach.”

So, in 2 John 7, they are the “deceivers” and are also known as the “antichrist.” I mean, there's nothing neutral here. 

You're either following the teaching of Christ, or you're following the teaching of antichrist. There's no neutral ground or fence-sitting here. 

And in 2 John 9, “the deceiver and the Antichrist”, referring to these false teachers. They are the ones who go too far or (ESV) “goes on ahead.” This means they go beyond scripture or the Bible. They start out quoting it but then they add their own tradition, own thoughts, and their own opinions such that they go too far. And what started out maybe as truth then turns in to lies and deceptions.

2 John 9: “Does not abide in the teaching of Christ” is referring to their teaching of Christ. But notice the end of verse 9: John has no kind words to say - he says they don’t have God! Which is a charitable way of saying they're damned and condemned. And given enough time, unless they repent, they will face God, but it will be in the judgment and they will have no advocate to plead their case. 

So, the key point of departure into heresy is always what we see here in 2 John 9: Not abiding in the teaching of Christ. 

Many today throw around the term “heretic” or “heresy.” The word heresy is a very flagrant word, and we need to use it properly.

If someone has a different understanding of baptism, that doesn't mean they're a heretic. 

So, what does this mean? Here are some examples of what it doesn’t mean:

—If someone has different eschatology (study of the end times) and the second coming of Christ, that doesn't mean they're a heretic. 

—If someone has a different understanding of church government, that doesn't mean they're a heretic. 

—etc.

It may mean they're wrong! However, a heretic is reserved for someone who is outside the Christian faith. It's reserved for someone who is under the wrath of God and who is teaching a damnable doctrine. 

And so, the point of departure is what we see here in 2 John 9—“does not abide in the teaching of Christ.” That's where they go astray. Given enough time, they will go further and further astray. And it will take in other areas of doctrine as well. Then they'll be coming up with really weird stuff. 

But this is the crack in the dam where the ocean begins to come through the dam is they have a faulty Christology. They have a faulty understanding of the person and work of Christ. And so, we want to fight our battles on the right battlefield.

So, that's what's being taught here and, specifically, in two areas: the humanity of Christ and the deity of Christ. 

The false teachers were denying the humanity of Christ. They were saying he was just some kind of a spirit / ghost that fell upon some person and then departed from this person. And while this spirit or ghost was upon him, he was the Christ. 

It was also a denial of the deity of Christ that he was created just like them. They might say: “He's higher than the angels, but he's lower than God.” In short, the false teachers of John’s day denied the deity of Christ. 

If you do this, you deny the Trinity. Why? Because you deny the deity of Christ, you deny the Trinity. You become a Unitarian. 

You also deny the virgin birth. Next, you deny what we call the “Hypostatic Union” of Christ, which is perfect deity and perfect humanity in one person. 

—You deny the sinless life. 

—You deny the substitutionary death. 

—You deny the bodily resurrection. 

—You deny the real ascension and the present enthronement. 

John is warning this woman that those who go too far and do not hold to the teaching of Christ: “They're trying to infiltrate your church. And they're using you as a side door to have access into the church.” 

Remember: the heart of the gospel is Jesus Christ. And if you're going to share the gospel, you talk about Jesus Christ. You advance to Jesus Christ as fast as you can in this conversation. Christ himself is the essence and the embodiment of the gospel.

Therefore, if you're wrong about Christ, you're wrong about the gospel. And if you're wrong about the gospel, you're wrong about every other place that matters.

Paul, along with other writers in the New Testament and some in the Old Testament, repeatedly warned about deceitful people infiltrating the church. 

—In Acts 20:29, Paul tells the elders in Ephesus that after he leaves, dangerous individuals will enter, harming the community.

—In 2 Corinthians 11:13, he describes these people as false apostles who pretend to represent Christ but deceive others. 

—Galatians 1:9 warns against preaching false teachings.

—Philippians 3:3 cautions about harmful individuals, comparing them to disease-spreading dogs. 

—Colossians 2:8 advises against being misled by empty philosophies. 

—1 Timothy 4:1 warns of people abandoning the faith due to deceitful doctrines. 

—2 Peter 2:1 discusses false prophets and teachers introducing destructive beliefs. 

—1 John 4:5 points out that those who belong to the world will be listened to by the world. 

—Jude 4 speaks of individuals who deny Jesus infiltrating churches and denominations. 

These warnings emphasize the ongoing need to be vigilant against such infiltration, which can occur in seminaries, churches, and leadership positions. These concerns are relevant to contemporary Christianity and highlight the importance of discernment within the church.

When dealing with false teachers, it's crucial to reject and not support them in any way. This rejection is clear and immediate, as stated in verse 10. The command "do not receive him into your house" is not negotiable; it's a present imperative, meaning it must be obeyed without delay (2 John 10). Welcoming a false teacher into your home gives them credibility, networking opportunities, and a base of operation. Unless it's to confront, rebuke, and correct them, they should not be welcomed at all.

Moreover, the command extends to not even giving them a greeting. This means no friendly encouragement, moral support, or personal affirmation should be offered. False teachers are to be shunned and shown the door, as they represent the epitome of danger and deception.

One might question whether this contradicts Jesus' command to love your enemies. However, true love entails preventing them from furthering their path toward destruction. It means waking them up to the reality of their spiritual peril, even if it requires drastic measures. Just as one would urgently awaken a sleeping person in a burning house, true love demands action to protect others and stand firm for the truth against those who distort it (Matthew 5:44; 2 John 10).

Finally, verse 11 provides the explanation for the strong stance outlined in verse 10. John realizes the need to clarify his position and why decisive action is necessary.

The word "for" at the beginning of verse 11 introduces the explanation for the preceding instruction. "For the one" refers to the True Believer, including the chosen lady mentioned in verse 1 and believers like us. "For the one who gives him," referring to the false teacher, "a greeting, a warm welcome, a personal encouragement," is implicated in his evil deeds. The term "evil" denotes actions that are ethically wicked, morally perverted, dark, devilish, demonic, sinister, and hellish. Even extending a greeting implies participation in these evil deeds.

The word "participates" is a verb form of "fellowship." By greeting the false teacher, one becomes an active partner, in league with him, sharing in his evil deeds. The same word is used in Romans 12:13 to mean "contributing to" and in Romans 15:27 as "have shared in," illustrating complicity in the wrongdoing.

This distinction draws a sharp line between God and the devil, between heaven and hell, between truth and error. It's significant enough that an entire book in the Bible, 2 John, addresses this issue. Despite its brevity, this epistle tackles a crucial vulnerability many have to falling prey to the devil's schemes through false teachers.

I'll conclude with a cross-reference to further emphasize this point, found in 2 Corinthians 6:14-16. The passage urges believers not to be yoked together with unbelievers, particularly in the context of ministry. We shouldn't rationalize partnerships with unbelievers as a pragmatic way to reach more people for Christ; unbelievers are our mission field, not our partners in ministry.

The rhetorical questions posed in these verses make it clear that righteousness cannot partner with lawlessness, light with darkness, Christ with Belial (a demon idol), or believers with unbelievers on a spiritual level. We, as the temple of the living God, are called to separate ourselves from such associations and not engage with what is unclean.

Conversely, wherever there is a negative directive, it often implies a positive one. Just as we are instructed not to welcome false teachers, the implication is that we should support and assist true preachers and teachers of the Word. It's crucial to be part of a church where the Word of God is honored and proclaimed, investing resources to support its spread. Loyalty to family ties or tradition should not overshadow fidelity to biblical truth. Standing in unity with those who uphold and proclaim the Word of God ensures that we contribute to the advancement of the gospel, avoiding complicity in spreading teachings contrary to Scripture.

In conclusion, the passage we've explored speaks in clear, black-and-white terms, reflecting the broader tone of the Bible. Rejecting false teachers is not a matter of ambiguity but a fundamental principle rooted in the Word of God.