For as Jonas was a sign unto the Ninevites, so shall also the Son of man be to this generation.
As Jonah's preaching was the sign to the Ninevites, so Christ's preaching was the sign to His generation, the Jews. Jonah's warning came from God and fulfilled its purpose even though the predicted event did not happen. The Ninevites met God's warning with repentance, and in their repentance God's grace was revealed among them.
Christ's hearers responded in a sharply different way, rejecting the word with indifference and scorn even though one greater than Jonah was among them. Despite that indifference, scorn, and rejection, Christ continued preaching until He completed His mission.
As Jonah's preaching was the sign to the Ninevites, so Christ's preaching was the sign to His generation, the Jews. Jonah's warning came from God and fulfilled its purpose even though the predicted event did not happen. The Ninevites met God's warning with repentance, and in their repentance God's grace was revealed among them.
Christ's hearers responded in a sharply different way, rejecting the word with indifference and scorn even though one greater than Jonah was among them. Despite that indifference, scorn, and rejection, Christ continued preaching until He completed His mission.