"The hearts of the two brothers were the same. Both sons resented their father's authority and sought ways of getting out from under it. They each wanted to get into a position in which they could tell the father what to do. Each one, in other words, rebelled -- but one did so by being very bad and the other by being extremely good. Both were alienated from the father's heart; both were lost sons.
"Do you realize, then, what Jesus is teaching? Neither son loved the father for himself. They both were using the father for their own self-centered ends rather than loving, enjoying, and serving him for his own sake. That means that you can rebel against God and be alienated from him either by breaking his rules or by keeping all of them diligently.
"It's a shocking message: Careful obedience to God's law may serve as a strategy for rebelling against God." (pp. 36-37)
By the way, I was introduced to these two books from the same source. There's a group of house churches out in western Washington state that offers leadership training seminars for people who want to explore their model of Christ-centered community as a way God is working to build his church today. Before you come, they tell you, "Read these two books."