"A good tree cannot produce bad fruit, nor can a bad tree produce good fruit" (Matthew 7:18).
Careful examination of a false prophet's teachings will always reveal unscriptural ideas and an absence of a solid, coherent theology. Often he will teach a combination of truth and error. But soon rather than later his teachings will prove the sort of teacher he really is. As Jesus said to the Pharisees, "You brood of vipers, how can you, being evil, speak what is good? For the mouth speaks out of that which fills the heart. The good man brings out of his good treasure what is good; and the evil man brings out of his evil treasure what is evil" (Matthew 12:34-35).
The creed of the false prophet cannot withstand any careful scrutiny by the pure light of the Word. The prophet Isaiah confirms this: "To the law and to the testimony! If they do not speak according to this word, it is because they have no dawn" (Isaiah 8:20).
False shepherds talk much about God's love, but not His wrath and holiness; much about how deprived of good things people are, but not about their depravity; much about God's universal fatherhood toward everyone, but not much about His unique fatherhood toward all who believe in His Son; much about what God wants to give to us, but nothing about the necessity of obedience to Him; much about health and happiness, but nothing about holiness and sacrifice. Their message is full of gaps, the greatest of which leaves out a biblical view of the saving gospel.
What makes us susceptible to the appealing messages of the false teachers? What are people looking for when they begin embracing error? How can we guard against this ourselves?