It seems like much of the usage this passage gets these days is to highlight the message of unity or its Christological aspects. Both are great uses of the text and this really is one of the great teachings on the Messiah’s ministry in scripture. However, both of those uses miss a point of this passage that emerges in the context of the letter.
Consider a possible summary of the paragraphs following the greeting in the letter thus far:
Paul thanks God for the Philippians’ partnership in advancing the gospel.-->
Paul’s difficult situation is serving to advance the gospel. -->
In fact, the ultimate purpose of the life of the believer is to glorify Christ advancing the gospel.-->
So walk and live in a manner that is worthy of the gospel.
It is all a very gospel heavy letter, not just gospel but the idea of its advance and the role of believers in that advance. Now, Paul goes on to list three examples related to this advancement starting with the example of Christ.
Just as Jesus gave Himself to make God’s plan, mission, and purpose complete, we are to give ourselves away to advance that same plan—mission—purpose. This is not just a passage about being humble or united as a body. It is a call to give our lives and our rights and our desires up for the sake of the gospel.
It is a call to die to self.