The reality is that Jesus is using historical events as metaphors:
The metaphorical use of historical events within a teaching subject was a frequent technique used by the Prophets through the lineage that included Jesus. This use of metaphor begins with the first three chapters of the Book of Genesis - both rich in symbolism and metaphorical language.
Metaphorical language is used throughout the Old Testament by the prophets as they tried to convey the Truth to their followers while keeping those who were not interested where they wanted to be - in the dark.
Jesus also used this technique in his teachings. Here is a statement explaining his technique of teaching using metaphors and symbolism:
"This is why I speak to them in parables: “Though seeing, they do not see; though hearing, they do not hear or understand." Matt. 13:13)
Jonah's warning to Nineveh
In the above statement, Jesus is referring to Jonah's warning to the people of the city of Nineveh. Nineveh is one of the oldest cities in the Middle East, with origins somewhere about 8,000 years ago. It became one of the largest and more important trading cities in the world during the 8th century BCE.
One of the issues with Nineveh was that it was the center for the worship of Ishtar - an idol/demigoddess of fertility, war and sex. So the populace was not much for devotion to the Supreme Being.
Jonah was a prophet and representative of God during the 8th century, and he was requested by the Supreme Being to preach to the people of the city and warn them of the consequences they would be facing should they continue in their ways:
"Go to the great city of Nineveh and preach against it, because its wickedness has come up before Me." (Jonah 1:2)But Jonah did not want to do this, so he ran off and jumped on a ship to Joppa. When a storm came up with heavy seas, Jonah told the crew he was to blame because he was running from his responsibilities. He convinced the crew to throw him off the boat, whereupon Jonah was swallowed by the whale.
And after Jonah took shelter in the Supreme Being within the whale and was rescued, God again instructed Jonah to warn the Ninevites.
To his surprise, the Ninevites took Jonah seriously. They donned sackcloth - even the king and the animals - and prayed for God's forgiveness:
The Ninevites believed God. A fast was proclaimed, and all of them, from the greatest to the least, put on sackcloth. (Jonah 3:12)The Supreme Being was merciful to the Ninevites - illustrating His compassionate nature. He forgave them and the city's coming destruction was averted:
When God saw what they did and how they turned from their evil ways, He relented and did not bring on them the destruction He had threatened. (Jonah 3:10)We should note that the word "threatened" is not a good translation choice for the Hebrew word עָשָׂה (`asah), which means "to do, word, make, produce" and "act with effect" and "bring about." The reality is that their coming destruction was a consequence of their behavior - not that God was threatening them - God warned them of the law of cause and effect - the law of consequences - and they were going to be subject to the consequences of their behavior.
So what is Jesus referring to as "the sign of Jonah"? It was Jonah's warning of the consequences of the Ninevites' activities. Jesus is making the same warning to those around him - this "wicked generation":
"For as Jonah was a sign to the Ninevites, so also will the Son of Man be to this generation."
A wicked generation
Jesus is thus warning those around him of the consequences of their activities as a collective group - a generation.
If we look at this historically, this did happen. Within a few decades of Jesus' departure, the Jewish-Roman wars broke out and Jerusalem was sacked and the Jewish institutions and their followers that had condemned Jesus were practically annihilated.
The Jewish-Roman wars began in the 66 AD and lasted at least through 135 AD, and the Romans slaughtered thousands of Jews and Christians alike before it was said and done.
But within this prediction also lies a deeper - metaphorically personal discussion.
For example, one might wonder what Jesus is referring to as the "Queen of the South." As Jesus is referring to Solomon, this is a reference to the Queen of Sheba's visit to Solomon around the thirteenth century BC - described in 1 Kings 10 and 2 Chronicles 9.
Queen of the South
The metaphorical use of the "Queen of the South" - taken from the Greek phrase βασίλισσα νότου which translates to "queen" and "south wind" or literally "queen of the south wind" - is referring to the fact that the Queen of Sheba came to visit Solomon with the intent of tripping him up with her "tests." Parts of the Talmud suggest that she also came to attempt to seduce Solomon.
The point is that not only did Solomon not succumb to her "tests," but he converted her. She had a change of heart and ended up glorifying the Supreme Being:
"Blessed be the LORD your God, who delighted in you, setting you on His throne to be king for the LORD your God! Because your God has loved Israel, to establish them forever, therefore He made you king over them, to do justice and righteousness." (2 Chronicles 9:8)
A change of heart
Both the men of Nineveh and Queen of Sheba had a change of heart after having contact with one of God's representatives. Jesus is saying that even they would condemn that society around Jesus. That was how bad it was.
If even the Queen of Sheba and the men of Nineveh could have a change of heart - then what to say of those hard-hearted persons of the "wicked generation" whom Jesus is talking to? They were doubting Jesus' teachings and eventually would allow him to be arrested and persecuted.
Certainly, Jesus is using these events as metaphors as he condemns those around him - both personally and as a group - who were rejecting Jesus' teachings. This is indicated clearly in the first sentence:
"This is a wicked generation. It asks for a sign, but none will be given it..."Jesus is referring to the followers and their teachers of the Jewish ecclesiastical institution who were waiting (and still are) for a Messiah to come forth to save them - a Messiah proven through miraculous "signs" - rather than simply hearing and following Jesus' teachings.
Jesus is God's representative
Yes, Jesus was condemning them because he was God's representative and he knew his teachings could save them - if they listened.
The men of Nineveh listened to Jonah. And the Queen of Sheba listened to Solomon. Jonah and Solomon were both God's representatives.
This relates specifically to Jesus' statements regarding: "now something greater than Solomon is here" and "now something greater than Jonah is here." Is Jesus just claiming to be really great here?
Certainly not. Jesus is speaking about the fact that he is God's representative, and he has come with the message - the teachings - from the Supreme Being. This is why he refers to "something." If Jesus were referring to himself as great he would have said "me" or "I."
We can see evidence of this in other statements by Jesus:
"For I have come down from heaven not to do my will but to do the will of Him who sent me." (John 6:38)These and other statements by Jesus indicate that Jesus is not referring to his own greatness, but the greatness of the One who sent him - the Supreme Being - and His message.
“My teaching is not my own. It comes from the One who sent me." (John 7:16)
"The One who sent me is with me; He has not left me alone, for I always do what pleases Him.” (John 8:29)
"But if I do judge, my decisions are true, because I am not alone. I stand with the Father, who sent me." (John 8:16)
And yes, the Supreme Being's message is greater than Solomon or Jonah - and Jesus was bringing that message to the people around him - many of whom were only concerned about seeing miracles and were fixed upon the prophets of the past. Meanwhile, Jesus was sent by God to teach them according to the current time and circumstance.
And what was the message Jesus was trying to give them from the Supreme Being - the message they were ignoring?
" 'Love the Lord your God with all your heart and with all your soul and with all your mind.' This is the first and greatest commandment. And the second is like it: 'Love your neighbor as yourself.' All the Law and the Prophets hand on these two commandments." (Matt. 22:37-40)