cont'd
God, trying to explain the reason for the change in the rule, they would have taken Jesus at his word.  If they thought Jesus was a nut job, they would have written off his words as just so much metaphor.  I've answered your question.

Again, however, the question isn;t "How do I think law-abiding Jews would have reacted when someone they knew, someone who had followed the law, was called an adulterer?  (A law abiding Jew who believed Jesus was the Christ would have seen himself as having been corrected by Christ, who was returning the law to the way it was in the beginning." Jesus said, "In the beginning, it was not always that way [that divorce was permitted."]).  
Nothing that Jesus told the Pharisees is remotely metaphorical, such an offending eye being plucked out.  
You ask:  "What was he trying to teach them?" Answer: That divorce is wrong, that in the eyes of God, there is no such thing as divorce except for adultery.
Now, answer my question, based on Jesus' own words.