At different times in his public preaching, Jesus was challenged by his opponents to give them a sign, a proof that he was sent by God. The common understanding was that he should work a miracle, something so spectacular that the opposition would have to believe that he was a prophet.
But Jesus refuses to give in. He doesn’t see a sign as just something spectacular, but as a way to salvation which brings about an inner transformation. In his mind, it is ‘the way of the cross’ which will do this, but his hearers aren’t ready for this yet.
In this passage, Jesus uses two similes from the Old Testament, known to his hearers. The first is from the parable of Jonah, the prophet who preaches to the corrupt city of Nineveh and brings about a change of heart.
The second is the account of the Queen of Sheba who visited King Solomon to learn from his wisdom.
What Jesus says is: here I am, Wisdom incarnate, the true Word of God, far greater than Solomon, and you, scribes and Pharisees will not learn from me. In fact, you keep trying to discredit me.
When the corrupt pagans of Nineveh heard the preaching of prophet Jonah, they repented in sackcloth and ashes, but you, Pharisees, are far away from any sort of repentance, even though I who am among you, am greater than the prophet Jonah!
No wonder then, these pagans – the people of Nineveh, and the Queen of Sheba – will denounce you on that last Judgment Day, for your hardness of heart.
Isn’t it so with us too? We keep demanding from God an irrefutable ‘sign’ of his power, when all about us are displayed signs of his love and providence – except that we are too prejudiced and preoccupied to see!