Matthew 7:15-20

15 "Beware of false prophets. They come to you disguised as sheep, but in their hearts they are vicious wolves.

16 You will know them by what they produce. "People don't pick grapes from thornbushes or figs from thistles, do they?

17 In the same way every good tree produces good fruit, but a rotten tree produces bad fruit.

18 A good tree cannot produce bad fruit, and a rotten tree cannot produce good fruit.

19 Any tree that fails to produce good fruit is cut down and thrown into a fire.

20 So you will know them by what they produce.