Why was that? It was because in rules, they had security, a way of proving that they were "good", and others needed to respect, and even take direction from them.
They aren't going to like the Kingdom then.
Romans 3:20 (New International Version)
20 Therefore no one will be declared righteous in his sight by observing the law; rather, through the law we become conscious of sin.
Romans 7:6 (New International Version)
6 But now, by dying to what once bound us, we have been released from the law so that we serve in the new way of the Spirit, and not in the old way of the written code.
Galatians 3:1-5 (New International Version)
Faith or Observance of the Law
1 You foolish Galatians! Who has bewitched you? Before your very eyes Jesus Christ was clearly portrayed as crucified. 2 I would like to learn just one thing from you: Did you receive the Spirit by observing the law, or by believing what you heard? 3 Are you so foolish? After beginning with the Spirit, are you now trying to attain your goal by human effort? 4 Have you suffered so much for nothing—if it really was for nothing? 5 Does God give you his Spirit and work miracles among you because you observe the law, or because you believe what you heard?
John 3:3 (New International Version)
3 In reply Jesus declared, "I tell you the truth, no one can see the kingdom of God unless he is born again." Footnotes:
- John 3:3 Or born from above; also in verse 7