Philippians 3.8 is one of my favorite verses in all of the Bible - "What is more, I consider everything a loss compared to the surpassing greatness of knowing Christ Jesus my Lord, for whose sake I have lost all things. I consider them rubbish, that I may gain Christ..." In this context Paul is arguing that he, like the "dogs" mentioned in v. 2, has an impeccable Jewish background, both in things that he was born into and things that he himself achieved. However, all that was to his profit, i.e., his Jewish background, he now considers loss (v. 7). Then he widens the scope in v. 8 to include "everything" under this category of "loss." Why? Because in comparison with knowing Christ Jesus as his Lord everything in Paul's world was rubbish, skubala, which is perhaps better translated as "crap" or even a more crass word (v. 8).
This verse (actually this entire passage - Phil 3.2-11) is central to understanding many things about Paul, at least as far as we are able. These verses shed light on Paul's back story, his post-Christ understanding of his pre-Christ self, his thoughts on how knowing Christ changed him, and what he believes the goals of his life in Christ are. These are all highly important things to keep in mind when attempting to articulate anything about Paul's theology. Perhaps the most influential one is that knowing Christ changed everything for Paul.
It should be noted and noted well that Paul does not claim in this passage that he was unhappy with his pre-Christ life when he was living it. Paul was not some sort of troubled soul prior to experiencing Christ, who found an answer in Christ to life's problems and was given psychological solice from his guilt-ridden existence (this point was famously made by Krister Stendahl in "The Apostle Paul and the Introspective Conscience of the West"). Instead Paul was happy expressing his love for God the way that he was taught, in the traditions of his fathers (Gal 1.14).
Then Christ was revealed to him (Gal 1.16), which relativized Paul's entire existence. Nothing that had seemed important before had the same weight anymore. What had been the center of Paul's life, the Law, now had its role usurped, replaced by Jesus Christ his Lord. It is my further contention that Paul's subsequent view of the Law and its place completely changed because of his encounter with Christ. Though Paul thought that the Law was still good, useful, and spiritual (Rom 7.12, 14), it now served a new purpose - to point people to the new reality that has been opened by Christ Jesus (Gal 3.24). Furthermore, the Law has not been superseded or nullified; not at all! It is fulfilled in those who believe (Rom 3.31), presumably through the power of the Spirit (Rom 8.4).
For Paul the Law's role and purpose was relavitized by Christ. Therefore, all of Paul's statements about the Law should always be read keeping this relatvitizing power of Christ in mind. Paul does not seem to have a problem with the Law per se, he seems to have a problem with people, even Christ-followers, who want to place it along side Christ at the center. If rightness with God could be attained in anyway outside of Christ, then Jesus' death was in vain (Gal 2.21). Thus, even though the religion that Paul practiced pre-Christ had a healthy dose of grace (cf. Sanders' covental nomism), compared to knowing Jesus it all took on new meaning (Phil 3.8).
I won't pretend that these thoughts are entirely original or that they will settle the debate on this issue. However, I do believe that Phil 3 should elicit much more attention than it actually receives. Perhaps the key that unlocks the Paul-and-the-Law safe is found there, namely the relavitizing power of Christ.