Read Matthew 12:34 Using Other Translations
O generation of vipers, how can ye, being evil, speak good things? for out of the abundance of the heart the mouth speaketh.
You brood of vipers! How can you speak good, when you are evil? For out of the abundance of the heart the mouth speaks.
You brood of snakes! How could evil men like you speak what is good and right? For whatever is in your heart determines what you say.