Matthew 7:15-20

15 Beware of false prophets, who come to you in sheep's clothing, but inwardly they are ravening wolves.

16 Ye shall know them by their fruits: Do men gather grapes from thorns, or figs from thistles:

17 Even so every good tree bringeth forth good fruit; but a corrupt tree bringeth forth evil fruit.

18 A good tree cannot bring forth evil fruit, neither [can] a corrupt tree bring forth good fruit.

19 Every tree that bringeth not forth good fruit is hewn down, and cast into the fire.

20 Wherefore by their fruits ye shall know them,