Jesus is direct. Jesus has no tolerance for the religious and their hypocritical ways.
I must take the warning from Jesus seriously. Jesus has given us all a sign. Jesus died, was buried, rose from the dead (the Jonah sign) and has ascended into heaven to be with God.
The Resurrection of Jesus is enough. That is his sign. God is God. God doesn’t have to prove himself to me. Never. Ever.
Some Pharisees and Sadducees were on him again, pressing him to prove himself to them. He told them, “You have a saying that goes, ‘Red sky at night, sailor’s delight; red sky at morning, sailors take warning.’ You find it easy enough to forecast the weather—why can’t you read the signs of the times? An evil and wanton generation is always wanting signs and wonders. The only sign you’ll get is the Jonah sign.” Then he turned on his heel and walked away. ~Matthew 16:1-4