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

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

Either make the tree good and his fruit good, or else make the tree corrupt and his fruit corrupt; for the tree is known by his fruit.

"O generation of vipers, how can ye, being evil, speak good things? For out of the abundance of the heart the mouth speaketh.

For out of the heart proceed evil thoughts, murders, adulteries, fornications, thefts, false witness, blasphemies: