For a good tree brings not forth corrupt fruit; neither does a corrupt tree bring forth good fruit. For every tree is known by its own fruit. For from thorns men do not gather figs, nor of a bramble bush gather they grapes. A good man out of the good treasure of his heart brings forth that which is good; and an evil man out of the evil treasure of his heart brings forth that which is evil: for of the abundance of the heart his mouth speaks. (Luke 6:43-45)