Jonah was sent to Nineveh to call that city to repentance. The people of Nineveh did not know Jonah's God, they were not versed in the commandments of the law, but their judgements were poor and their actions sinful. At the preaching of Jonah they saw themselves as never before, and saw the possibility of what they might be - and repented. They found in Jonah a word of hope and a possibility of change rather than a blanket condemnation - and repented. They found possibility and most importantly, mercy.
Jesus reminds his listeners of the people of Nineveh who repented at the words of Jonah, and of the queen of the south who traveled a great distance to hear the wise words of Solomon. They came, they heard and saw, they embraced words that were inspired by God but earthly and limited. And Jesus says that they will rise up and condemn this generation. Why? Because this generation has been shown the better path, has been given a greater opportunity - not by a wise king or a reluctant prophet - but been embraced by the mercy of God, called to life by the author of all that is good, and given a chance to lay aside the works of darkness and live in the Light. And this generation waffles and resists. There IS something greater at work here, and it is mercy and love. There IS something at work here and it is the person of Jesus Christ as our Lord and Savior.
Thursday Prayer over the People
May the mercy they have hoped for, O Lord,
come to those who make supplication to you,
and may the riches of heaven by given them,
that they may know what is right to ask
and receive what they have sought.
Through Christ our Lord.