The sign of Jonah

Key verses

Psalm 36:5-6 - Your love, O Lord, reaches to the heavens, your faithfulness to the skies.  Your righteousness is like the mighty mountains, your justice like the great deep.

Matthew

Jesus was talking to the Pharisees and Sadducees, people who knew the law inside and out and yet didn't follow the heart of God's message.  Perhaps this is what Jesus was getting at when he said that their generation would only receive the sign of Jonah.  "A wicked and adulterous generation looks for a miraculous sign, but none will be given it except the sign of Jonah."  These are just my thoughts, but I'm thinking the sign of Jonah is that, just like Jonah heard God's message but didn't fully accept it, so these people hear what Jesus is saying, but aren't accepting his message.  Instead of the Jews accepting Jesus, the Gentiles will hear and repent, just like the Ninevites did.