Philippians is known as the 'epistle of joy,' written by Paul from prison to express gratitude toward the Philippian church for their financial and spiritual support. Despite his difficult circumstances, Paul emphasizes Christian joy, unity in the church, and Christ's sufficiency in all situations. The letter includes one of the most profound christological passages in the New Testament (2:5-11) and teaches about contentment, perseverance in faith, and the eternal perspective that should characterize Christian life.