In today's Gospel reading from Matthew 12, some of the scribes and Pharisees demanded to see a sign from Jesus. Any unfaithful generation would not believe until it sees some kind of proof. People in general easily accept what the new media put out or what their friends tell them, but when it comes to hearing about Jesus, they readily shut their mind. How come? I would say it's because deep down they know that they are sinners and, naturally, any mention of God would make any sinner feel uneasy.