Matthew 7:15-20 (HCSB) Beware of false prophets who come to you in sheep's clothing but inwardly are ravaging wolves.
You'll recognize them by their fruit. Are grapes gathered from thornbushes or figs from thistles?
In the same way, every good tree produces good fruit, but a bad tree produces bad fruit.
A good tree can't produce bad fruit; neither can a bad tree produce good fruit.
Every tree that doesn't produce good fruit is cut down and thrown into the fire.
So you'll recognize them by their fruit.