One of my other pet pseudo-academic theories that I occasionally like to argue is that Phillipians--not Ephesians, not Romans--is actually at the core of Paul's theology.
It's a crazy thesis, and no NT scholar that I know would ever make it in public, which is one of the criteria for holding it in case you ever find yourself trapped around the punch-bowl with a bunch of New Testament ge---scholars.
At any rate, allow me to endorse Fred Sanders' take about this "sweet and unsystematic" book:
As a result, Philippians is in the odd category of being a favorite neglected book. Most of us have experienced Philippians as a loose collection of favorite verses, without much sense of what binds it together, or of what distinct contribution it makes as a book to our understanding of the Christian life. But it’s a book worth spending concentrated time with, to soak in its unique power. Its central idea can probably be seen best at the point where Paul describes Christ’s condescension in order to encourage the church to have the mind of Christ in their selfless service and Christlike humility. Paul writes from this perspective, and it makes Philippians a great help in seeing our lives correctly in this “crooked and depraved generation.”
Dr. Sanders doesn't say this, but 'unsystematic' doesn't mean 'ununified.'
Paul's description of Christ's condescension is the centerpiece of the book, but it is reinforced by the specific relationships that Paul and his associates have with the church in Phillipi, relationships that are grounded in and motivated by the presence and working of the Holy Spirit.
And it is buttressed by Paul's own personal experience of suffering, an experience that allows him to establish himself as an example to imitated by the Church at Phillipi.
All of which makes Phillipians Paul's most personally vulnerable letter. As the intensity of Paul's relationship with the Phillipians is encompassed by the Gospel and the working of Christ, Phillipians provides unique insight into the dimensions of the Gospel within local communities.
There's more to be said, of course, but Dr. Sanders is right in his assertion that Phillipians has a unique power. It is a book worth spending considerable time with.