Paul is telling the church in Philippi that they will encounter visitors who will claim they are lacking in righteousness. Paul himself, however, could boast more than anyone—he was a Hebrew of Hebrews, a Pharisee, and had incredible zeal for God. Yet, he considers all of these things as garbage compared to knowing Christ. The same applies to us: we often try to earn righteousness on our own, often by telling others, "I’m a good person." Paul wants us to recognize that the issue isn’t with righteousness itself, but with where we think it comes from. We continuously seek approval, whether from others or from within, approval that only God can grant. So, how do we secure righteousness from God? Christ became sin so that we could become the righteousness of God. Through this, we are made right with God, which empowers us to live out the good works we are called to do, all because of our standing with God through Christ and this is what he wants the church to understand. They are righteous already because they know Christ!