Watch out for false prophets. They come to you in sheep’s clothing, but inwardly they are ferocious wolves.
Life Application Study Bible, NIV footnotes:
False prophets were common in Old Testament times. They prophesied only what the king and the people wanted to hear, claiming it was God's message. False teachers are just as common today. Jesus says to beware of those whose words sound religious but who are motivated by money, fame, or power. You can tell who they are because in their teaching they minimize Christ and glorify themselves.
I like the rest of that passage. It reads:
By their fruit you will recognize them. Do people pick grapes from thornbushes, or figs from thistles? Likewise every good tree bears good fruit, but a bad tree bears bad fruit. A good tree cannot bear bad fruit, and a bad tree cannot bear good fruit. Every tree that does not bear good fruit is cut down and thrown into the fire. Thus, by their fruit you will recognize them. Matthew 7:16-20
Footnotes:
We should evaluate teachers' words by examining their lives. Just as trees are consistent in the kind of fruit they produce, good teachers consistently exhibit good behavior and high moral character as they attempt to live out the truths of Scripture. This does not mean we should have witch hunts, throwing out church school teachers, pastors, and others who are less than perfect. Every one of us is subject to sin, and we must show the same mercy to others that we need for ourselves. When Jesus talks about bad trees, he means teachers who deliberately teach false doctrine. We must examine the teachers' motives, the direction they are taking and the results they are seeking.
The thing that I would add to these footnotes would be to evaluate all teaching in light of scripture. If we are familiar with scripture through reading, studying and meditating on God's truth, we are more apt to have open eyes to false teaching.
