Philippians is a love letter that Paul likely wrote from a Roman prison. Paul is encouraging this church, which he planted by God’s grace on his second missionary journey, to have the “mindset” consistent with the gospel, and to live a “cruciform” lifestyle. The word “gospel” occurs more in this letter proportionately than any other NT letter. Another important word-group is joy, which is often commanded in this book. The concern here is how to live in the face of suffering.
The key passage in the letter is 2:6-11. The church is called to be like Christ in humility and selfless service thereby promoting unity. Paul is for the advancement of the gospel no matter the cost. For him, “to live is Christ and to die is gain” (1:21). He stresses the worthlessness of legalism and the gain in knowing Christ and becoming like him in his death (3:7-11). We are to rejoice always in the Lord and get rid of anxiety through prayer and thanksgiving (4:4-7). Lastly, he thanks the Philippians for their faithful support of his ministry and blesses them (4:19).