For certain persons have crept in unnoticed, those who were long beforehand marked out for this condemnation, ungodly persons who turn the grace of our God into licentiousness and deny our only Master and Lord, Jesus Christ. Jude 4

It’s hard for me to imagine someone actually infiltrating the church surreptitiously in order to corrupt it, but this was exactly Jude’s focus. We’re not clear on who the perpetrators were, but the problem was acute enough for Jude to drop his initial intent to address our “common salvation” to issue his plea to “contend earnestly for the faith.”

He starts by pointing out that such subterfuge had been predicted. Where you might ask? Perhaps one needs only to harken back to the strategy of Satan in the garden, and observe his methodology down through time. He’s a counterfeiter and deceiver, an “angel of light” wanting only to destroy all that which God has made or ordained, including his church. We read that his plight and that of his accomplices is certain, condemnation and destruction, but sadly in many instances not before they leave a painful mark. Knowing what he’s up to will limit the damage and keep many from falling.

The Apostle Peter, one of Jude’s influencers, echoes Jude’s warning.

But false prophets also arose among the people, just as there will also be false teachers among you, who will secretly introduce destructive heresies, even denying the Master who bought them, bringing swift destruction upon themselves. 2 Peter 2:1

How can we tell someone’s a wolf in sheep’s clothing? For one, at their core, they are ungodly. Whereas we through his Spirit should be attuned to even the slightest deviation from the will of God, sound teaching, and righteous living, these people will seem to push the limits of God’s grace. They’ll also introduce questions that diminish the sovereignty of God, the lordship of Jesus, or the inerrancy of scripture.

Practically, in order for “false teachers” to be successful, they’ll need to be pushing some agenda that’s slightly off the mark. Just think of Satan in the garden with Eve or in the wilderness with Jesus. My antenna is always up for strange statements that are offered “when the coast is clear.” I’m not talking about typical disagreements on theology or eschatology that do not veer off the reservation, but out and out false doctrine. I distinctly remember a conversation with a former worship pastor about his musings on the concept of annialation, the heretical thinking that the wicked will cease to exist after this life. This is a blatantly cancerous notion.

All this points to the need for us to be well taught and controlled by the Holy Spirit. This is precisely why Jude is urgently warning us to be on our guard.

But you, beloved, building yourselves up on your most holy faith, praying in the Holy Spirit, keep yourselves in the love of God, waiting anxiously for the mercy of our Lord Jesus Christ to eternal life. Jude 20–21

Nevertheless, to leave no doubt, verses 5-8 are provided to help us spot, root out, and if possible, save the evil influencers amongst us.