When the crowds were increasing, he began to say, “This generation is an evil generation. It seeks for a sign, but no sign will be given to it except the sign of Jonah.  For as Jonah became a sign to the people of Nineveh, so will the Son of Man be to this generation.  The queen of the South will rise up at the judgment with the men of this generation and condemn them, for she came from the ends of the earth to hear the wisdom of Solomon, and behold, something greater than Solomon is here.  The men of Nineveh will rise up at the judgment with this generation and condemn it, for they repented at the preaching of Jonah, and behold, something greater than Jonah is here.
 “No one after lighting a lamp puts it in a cellar or under a basket, but on a stand, so that those who enter may see the light.  Your eye is the lamp of your body. When your eye is healthy, your whole body is full of light, but when it is bad, your body is full of darkness.  Therefore be careful lest the light in you be darkness.  If then your whole body is full of light, having no part dark, it will be wholly bright, as when a lamp with its rays gives you light.”
(Luke 11:29-36 ESV)