Matthew 12:33-39

33 "Either make the tree good, and its fruit good; or make the tree bad, and its fruit bad; for the tree is known by its fruit.

34 You brood of vipers! how can you speak good, when you are evil? For out of the abundance of the heart the mouth speaks.

35 The good man out of his good treasure brings forth good, and the evil man out of his evil treasure brings forth evil.

36 I tell you, on the day of judgment men will render account for every careless word they utter;

37 for by your words you will be justified, and by your words you will be condemned."

38 Then some of the scribes and Pharisees said to him, "Teacher, we wish to see a sign from you."

39 But he answered them, "An evil and adulterous generation seeks for a sign; but no sign shall be given to it except the sign of the prophet Jonah.