Matthew 7:15-20

15 "Beware of the false teachers--men who come to you in sheep's fleeces, but beneath that disguise they are ravenous wolves.

16 By their fruits you will easily recognize them. Are grapes gathered from thorns or figs from brambles?

17 Just so every good tree produces good fruit, but a poisonous tree produces bad fruit.

18 A good tree cannot bear bad fruit, nor a poisonous tree good fruit.

19 Every tree which does not yield good fruit is cut down and thrown aside for burning.

20 So by their fruits at any rate, you will easily recognize them.