Matthew 12:34-38
34O generation of vipers, how can ye, being evil, speak good things? for out of the abundance of the heart the mouth speaketh.
35A good man out of the good treasure of the heart bringeth forth good things: and an evil man out of the evil treasure bringeth forth evil things.
36But I say unto you, That every idle word that men shall speak, they shall give account thereof in the day of judgment.
37For by thy words thou shalt be justified, and by thy words thou shalt be condemned.
38Then certain of the scribes and of the Pharisees answered, saying, Master, we would see a sign from thee.
(KJV)