Pharisees demand a sign from Jesus - Jesus rebukes them and acknowledges his true brothers. (Matthew 12:38 - 12:50) - Bible Blender
The Pharisees are unable to exercise faith. They ask Jesus to produce a sign instead. The Bible makes it clear that signs are a gift, not a demand. Signs cannot be required for belief – it would contradict the principle of faith. And the principle of faith ensures mankind requires a token of effort to attain God’s good grace.