The crowds increased and Jesus responded to the request for ‘a sign from heaven’ from verse 16. Jesus said the sign is himself/the Son of Man just as Jonah was a sign for the Ninevites in the Old Testament. The Ninevites responded to Jonah. The Queen of the South responded to Solomon. They need to respond to him.
I’m not sure why Jesus started talking about light/darkness and the eye at this point. What I do understand is the sensation of being full of light and discerning if there is darkness in me. This passage is a ‘prayer passage’ for me…a prayer that I will be full of light and not darkness…a prayer that when darkness creeps into and out of my heart, I will be aware of it and turn to be filled with light.
Jesus accepted an invitation to eat at a Pharisee’s home. Jesus just walked in and reclined at the table ready to eat. He didn’t stop for the ritual cleansing like he ‘should’ have. Jesus began speaking woes to the Pharisees and the experts in the law. Jesus confronted them: turn from your internal greed and wickedness and be generous to the poor; turn from your precise tithing even your garden herbs and practice justice and the love of God; stop seeking the important seats and respectful greetings when you’re shopping; graves were marked so people would not become defiled by coming in contact with a grave…the Pharisees were like unmarked graves, defiling people without the people being aware; stop loading people down with endless lists of laws; by building tombs for the prophets that your ancestors killed you are endorsing what they did when they killed the prophets; and you’ve taken away the key to knowledge and have hindered those who would enter into knowledge and obtain it.
Needless to say, they didn’t take too kindly to Jesus’ words and were just waiting for him to make a wrong move or to say something falsely.