Are we ignoring the signs?
1. They ask - give us a sign. Jesus had just healed a possessed man. They refused to see. You will get the sign of Jonah. (Judgement and God's patience and mercy). The Queen of the South - she is totally amazed at Solomon's wisdom. Jesus is greater, but they refused. Similarly with our generation. Signs are no guarantee of belief.
2. Fix your eyes. Jesus is the light that shines before men. The health of eye is what matters. What our spiritual eyes focus on is important. People with 20-20 vision failed to see who Jesus was. We can be distracted by false light, or refusal to see. (eg Las Vegas)