Modern Bible translations seem to suggest that Luke 11:33-36 is related to Luke 11:29-32. If this is true, I can’t figure out the connection. Please explain this to me. Thanks.
I am very far from being the world’s expert on Luke 11:29-36. One thing I would point out is that the statement that the eye is the lamp of the body is also found within the Sermon on the Mount in Matthew 6:22-23. It that context it certainly does not seem to bear any obvious relationship to the "sign of Jonah." It seems to me that the sign of Jonah is a challenge to the Jews that even the Gentiles will be open to the message of Jesus. If they refuse the one sent to them by God, when they had been prepared specially by God to receive the Savior, then a special kind of judgment may come on them.
How this will relate to Luke 11:33-36 is not completely obvious, but let me suggest something. Here, if you look at Matthew 6, Jesus seems to be saying (the eye is the lamp of the body) that if you miss the most important point, it does not really matter if you get a smaller point. I can see a connection thematically here to the sign of Jonah. Jesus seems to be saying that if the Jews have the Old Testament and all the wonderful advantages of having the Old Covenant, but miss the kingdom of God–miss Jesus who is the whole point of the Old Covenant–then it is all really of no value. So, I see a bit of a parallel here. I am sure that some commentators will find a relationship between these verses beyond what I am pointing out here. What I would say is that you should read what these writers have to say, take it all with a grain of salt, and then should not worry all that much who is right. Both little scripture sections–Luke 11:29-32 and Luke 11:33-36–stand on their own and if there is some sort of relationship between them, then that is all the better, but probably not terrifically important in the scheme of things. To summarize, I see much of the content of Luke 11, including the six woes and the Jesus vs Beelzebub, to be a diatribe against those Jews who, despite all advantages, are unable to see in Jesus the one who God told them was coming–the Messiah. Missing the "sign of Jonah" and having a bad eye/lamp of the body/guiding knowledge of Jesus are two examples of this.