Jesus points out an amazing thing in this passage in regard to the blindness of Pharisees and Sadducees. These learned men of the Torah, who battled one another for political control of Israel, could see the beauty of the physical sky … the heavens … but were blind to the beauty of God’s Sovereignty … blind to the presence of holiness in their midst. They demanded “a sign from heaven” but could not see the truth of Jesus and the Kingdom of Heaven right before them. The Sign of Jonah is Jesus' final death, burial, and resurrection. The only sign that these Pharisees and Sadducees would see is Jesus coming out of the grave after three days. But their interpretation of Heaven missed the truth. They were blind to the reality in front of them. It is unfortunate that many people struggle with the same spiritual blindness today. We often focus on the everyday reality in front of us, but totally miss the voice or hand of God when it is plain that HE is doing a great thing right in our line of vision. We miss the truth of salvation and of Jesus's Authority because of his death, burial, and resurrection. God reigns from his holy temple in heaven and the sign from heaven that HE gives is the death, burial, and resurrection of HIS Son. The sign he gives from heaven is the establishment of the Kingdom of Heaven in the humble and repentant hearts of sinful humanity.