Luke 11:29 - 36  Jesus issues a warning and a judgement against the "this generation".   He calls them "a wicked generation " for seeking a sign.  He will not be manipulated into performing miracles on demand, just for their purposes.  The Father's purposes are His priority - so a sign will be given - one that should be sufficient for any man, any generation - "the sign of Jonah".   "... so shall the Son of Man be to this generation."  How was Jonah a sign to the Ninevites?  Jonah reluctantly preached judgement to the Ninevites, and they repented.  Was the fact that they had heard his story about being in the belly of a whale for 3 days a factor in their repentance?  Possibly.   We know Jesus would spend 3 days in the grave before He is resurrected... that "sign" is the only one needed for men to repent of their sins and turn to God.

Jesus makes 2 proclamations;
Verse 31 - "something greater that Solomon is here."
Verse 32 - " and behold something greater than Jonah is here,"
In Matthew 12: 6  Jesus also says that " something greater than the temple is here."
The main point seems to be that these things - Solomon's wisdom, Jonah's testimony, and the temple's splendor - are great things - but nothing in comparison to the Presence of the Son of God Who has come to provide eternal salvation.  The fact that "this generation" is rejecting Him will bring a judgment greater than anything other.

Verses 33-36 - Jesus talks about light and the eye -
We don't hide a burning light.
The eye is the lamp of the body.
Through a healthy eye - light comes in.
Through a bad eye - darkness remains.
" Then watch out that the light in you may not be darkness."(v35)

The Light of the world - Jesus had come to earth and was consistently preaching the Truth.  No greater light had ever been given to men, and this generation had the opportunity to see it first hand. Nevertheless, they remained in darkness, rejecting the true Light.
We each have that same choice.  We can open our eyes and receive the Word, which is a light to our feet and a lamp for our path - to the Light of the World.  Or we can remain in darkness.

Father in heaven, You have given us the Light... "In Him was life and the life was the light of men. And the light shines in the darkness and the darkness did not comprehend it"  O Lord of all creation - open our eyes to fully receive the Light and the life in Jesus Christ.  May we comprehend the greater One - receive Him and be filled with the His Spirit.  Make our lives a reflection of this great Light.
We offer ourselves to You, through Him, amen.