On July 16, 1945, a handful of scientists and military officials gathered in New Mexico to witness the detonation of the world's first atomic bomb -- an event that heralded the end of World War II and seemed to usher in an era of American military superiority that would last decades. 

But not everything was as it appeared to be.  More specifically, not everyone attending the detonation was who they appeared to be.

Nestled among the inner circle of experts who spearheaded the "Manhattan Project" was Klaus Fuchs, a German-born, British physicist who was in fact a Soviet spy.  As U. S. military commanders around him congratulated themselves on their unparalleled new weapon, Fuchs reveled in knowing that, thanks for him, blueprints for the same kind of bomb were already in Russian hands.

British intelligence caught up with Klaus Fuchs in 1950 and his confession revealed a devastating Soviet spy ring that had been stealing U. S. military secrets for a decade.  His cohorts, Julius and Ethel Rosenberg, were arrested and ultimately executed.  Fuchs spent nine years in prison, but the damage was already done.

Years sooner than anyone expected, the Soviet Union detonated its first atomic bomb.  The Cold War escalated to dangerous new heights as the United States -- caught unaware -- engaged the Soviets in a nuclear arms race that would keep the world fearful of nuclear annihilation for nearly fifty years.

Isn't it amazing the kind of damage a well-placed enemy operative can inflict?  Years of research and development and layers of security, all undone because Fuchs and his cohorts slipped past the defenses wearing the mask of friendship.

Perhaps nowhere is that principle more evident than in how God's enemies go after His church.  throughout history, Satan has launched innumerable overt attacks on the church -- everything from persecution to false religion.  But the most damaging attacks by far have come from within.  They have been the result of inside operators -- pretenders -- who infiltrated the church.

False teachers within the church can take many forms -- some you may even recognize.  Some work their way into the leadership.  They may teach your child's Sunday school class or lead your worship.  Others become elders or deacons, where they have a voice in how your church handles discipline or how it manages its financial resources.  In the most extreme -- and most devastating -- cases, spiritual double agents ascend to the pulpit.

Whatever form they take, false teachers follow a similar pattern.  Claiming to love the church, they work behind the scenes to hinder its effectiveness.  Pretending to speak truth, they twist Scripture for personal gain and shipwreck the faith of many along the way.  Like Klaus Fuchs, false teachers appear to be on your side.  They appear to profess the right gospel.  They seem to proclaim the right doctrine.  On the surface, at least, they present the perfect case for spiritual piety.  Beneath the surface, however, they practice deceit.

Left unchecked, their deceit eats away at the church in a number of ways.

First, false teachers sow disunity and breed confusion.  They introduce strange doctrines and interpretations and promote unbiblical standards and practices.  They disagree with other teachers and seek to generate their own following within the congregation, causing dissension and church splits.  They add their own material to Scripture and take away whatever they don't like and the lack of doctrinal unity confuses and discourages other members of the flock.

False teachers also discredit the name of Christ.  Whenever a high-profile false teacher is exposed -- whether he's caught in adultery or in siphoning money from the church the result is the same.  The watching world uses his hypocrisy as an excuse to dismiss Christ.  Christians, they conclude, are all fakes who claim to be different, but underneath the surface are just like everybody else.  In the way, false teachers ultimately reinforce the world's contention that Christ has no power to change lives.

Finally, false teachers extinguish the church's power to direct lost souls to the gospel.  Satan's ultimate objective in using false teachers is to distort the gospel and prevent people who come to church from hearing what they need to hear.  If he can pollute God's truth with enough lies and half truths, he can render it ineffective to save.

Given the kind of damage false teachers can cause the church, it's no wonder God warns us about them so vividly and aggressively in His Word.  Paul and Peter wrote about them, as did Jude.  Jesus Himself cautioned His disciples about them on several occasions.

And God's Word provides more than just warnings.  It also tells us how you can spot false teachers for who they are.  It paints a disturbing portrait of how false teachers operate so you recognize them before they destroy your church.

For in depth studies on false teachers, check out Dr. MacArthur's sermons on 2 Peter and Jude.  These are available at Grace To You by calling 1-800-55-GRACE.