Throughout history, deadly epidemics have ravaged mankind. In the fourteenth century, the infamous Black Death (an outbreak of bubonic plague) killed millions in Europe. Cholera, diphtheria, malaria, and other sicknesses have ravaged towns and cities. Our generation has witnessed the rapid spread of the fatal disease Acquired Immune Deficiency Syndrome (AIDS). More deadly than any of those diseases, however, is the plague of false teaching that has afflicted the church throughout its history. While illness may kill the body, false teaching damns the soul.

Like AIDS and the plague, false teaching has a definite, observable pathology—the elements of abnormality that characterize a disease. Scientists study the pathology of a disease to better equip themselves to recognize it and to combat it.

Every leader in the church should be a spiritual pathologist, able to discern deviations from spiritual health. Only then will he be equipped to diagnose the deadly disease of false teaching, and to do what is necessary to check its spread among his people. Paul warned of the subtle danger of satanic lies, describing their purveyors as

false apostles, deceitful workers, disguising themselves as apostles of Christ. No wonder, for even Satan disguises himself as an angel of light. Therefore it is not surprising if his servants also disguise themselves as servants of righteousness, whose end will be according to their deeds. (2 Corinthians 11:13–15)

It takes careful discernment to see that the light is really darkness. Paul taught Timothy how to diagnose satanic darkness masquerading as divine light. Here’s how he described the key symptoms that identify those infected with the spiritual disease of false teaching:

If anyone advocates a different doctrine and does not agree with sound words, those of our Lord Jesus Christ, and with the doctrine conforming to godliness, he is conceited and understands nothing; but he has a morbid interest in controversial questions and disputes about words, out of which arise envy, strife, abusive language, evil suspicions, and constant friction between men of depraved mind and deprived of the truth, who suppose that godliness is a means of gain. (1 Timothy 6:3-5)

The first symptom of false teachers is what they affirm. A false teacher “advocates a different doctrine.” False teaching may take many forms. It may deny God’s existence, or teach error about His nature and attributes. It may deny the Trinity. Error about Christ’s Person and work is also common in false systems. Those who deny His virgin birth, sinless perfection, substitutionary death, bodily resurrection, or future return show signs of a dangerous infection. False teachers also teach error about the nature, Person, and work of the Holy Spirit. Yet another strain of the disease of false teaching denies the authenticity, inspiration, authority, or inerrancy of Scripture.

At the same time, another mark of false teachers is what they deny. Their teaching not only affirms error, but also “does not agree with sound words, those of our Lord Jesus Christ” (1 Timothy 6:3). False teachers are not in agreement with spiritually wholesome and beneficial words. That believers need to pay attention to sound, healthy teaching is repeatedly emphasized in the Pastoral Epistles (cf. 1 Timothy 1:10; 2 Timothy 1:13; Titus 1:9; 2:1).

False teachers are not committed to Scripture. They may speak of Jesus and the Father, but the heart of their ministry will not be the Word of God. They will either add to it, take away from it, interpret it in some heretical fashion, add other “revelations” to it, or deny it altogether.

A third symptom of false teachers is their rejection of “the doctrine conforming to godliness” (1 Timothy 6:3). The ultimate test of any teaching is whether it produces godliness. Teaching not based on Scripture will result in an unholy life. Instead of godliness, the loves of false teachers will be characterized by sin (cf. 2 Peter 2:10-22; Jude 4, 8-16).

The attitude of false teachers can be summed up in one word: pride. It takes an immense ego to place oneself as judge of the Bible. Such egotism blatantly usurps the place of God. “Conceited” (1 Timothy 6:4) is from tuphoō, and it implies arrogance, an inevitable mark of false teachers. To set up one’s own teaching as superior to the Word of God is the epitome of arrogance. False teachers have an overinflated sense of their own importance, not hesitating to rebel against God and His Word. That merely confirms, however, that they are infected with a deadly spiritual disease.

False teachers are also exposed through their mentality. Although a false teacher may be filled with pride over his supposed knowledge, Paul says that in reality “he . . . understands nothing” (1 Timothy 6:4). All of his imagined intelligence, pretended scholarship, and supposed deeper insights amounts to mere foolishness to God (Romans 1:22; 1 Corinthians 2:9–16). Lacking insight into spiritual truth, his wisdom “is not that which comes down from above, but is earthly, natural, demonic” (James 3:15). Those who know and believe the Word of God have far more insight into spiritual reality than the most educated heretic.

Instead of focusing on the truth, false teachers have “a morbid interest in controversial questions and disputes about words” (1 Timothy 6:4). They indulge in pseudointellectual theorizing rather than in productive study of and submission to God’s Word.

False teaching also fails in its inability to produce unity (1 Timothy 6:4-5). The word battles of false teachers result in chaos and confusion. “Envy” is the inward discontent with the advantages or popularity enjoyed by others. It results in “strife,” which often manifests itself in the “abusive language” of slander and insult. The net result of false teaching is “constant friction.” False teachers constantly rub each other the wrong way. That helps spread their spiritual disease, much as sheep might rub together and infect each other. False teaching can never produce unity. Only the truth unifies.

The external cause of false teaching is satanic deception (cf. 1 Timothy 4:1). The internal cause, however, is the depraved or unregenerate mind of the false teacher. “The mind set on the flesh,” writes Paul, “is hostile toward God” (Romans 8:7). Such a mind does not function normally in the spiritual realm; it does not react normally to truth. Being natural men, false teachers cannot understand the things of God, which seem foolish to them (1 Corinthians 2:14). As a result, “God gives them over to a depraved mind” (Romans 1:28; cf. Ephesians 2:1–3; 4:17–19).

The spiritual condition of false teachers is critical; they are in a state of apostasy. “Deprived” (1 Timothy 6:5) indicates that someone or something pulled them away from the truth. That does not imply they were saved, but that they had contact with the truth. Like those described in Hebrews 6:4–6, they were thoroughly exposed to the truth, but rejected it.

Unfortunately, their prognosis is not hopeful. Their spiritual condition is terminal. Those who are deprived of the truth are headed for judgment. Hebrews 6:6 solemnly warns of such men that “it is impossible to renew them again to repentance, since they again crucify to themselves the Son of God, and put Him to open shame.” Peter says that they bring “swift destruction upon themselves” (2 Peter 2:1). The severest hell will be reserved for those who, having been exposed to the truth, turned away from it (cf. Hebrews 10:26–31).

Finally, false teachers have a simple motivation: money. They “suppose that godliness” (1 Timothy 6:5, used sarcastically of their false piety) will bring them such gain. Unlike Paul, they cannot say, “I have coveted no one’s silver or gold or clothes” (Acts 20:33). Put simply, they are not “free from the love of money” (1 Timothy 3:3).

The pathology of false teachers is clear. They deny the truth, and their teaching does not produce godly living. They are arrogant and ignorant of spiritual truth. They spend their time in foolish speculations that lead only to chaos and division. Having forsaken the truth, they face eternal destruction. And they serve money, not God. The church must take extreme care not to allow these men to spread their deadly disease. The resulting epidemic would be tragic.

(Adapted from The Macarthur New Testament Commentary: 1 Timothy.)