The verse Philippians 3:20 states, “But our citizenship is in heaven, and we eagerly await a Savior from there, the Lord Jesus Christ” (NIV). The Apostle Paul is traditionally recognized as the author of the Book of Philippians, which is one of the Pauline Epistles in the New Testament.

From an evangelical Christian perspective, several key points about Paul as the author include:

1. **Apostolic Authority**: Paul, originally known as Saul of Tarsus, was a prominent Apostle who played a critical role in the spread of Christianity in the first century. His apostolic authority comes from his dramatic conversion experience on the road to Damascus, where he encountered the risen Christ (Acts 9:1-19).

2. **Context of the Letter**: The Epistle to the Philippians was written during Paul’s imprisonment in Rome, likely around AD 61-62. The letter is addressed to the Christian community in Philippi, a city in Macedonia, where he had established a church on his missionary journeys.

3. **Themes**: In Philippians, Paul emphasizes themes such as joy, unity, humility, and the importance of living a life worthy of the gospel. Philippians 3:20 highlights the concept of Christian citizenship, implying that believers’ ultimate allegiance is to heaven rather than the earthly kingdom.

4. **Encouragement and Exhortation**: Paul wrote this letter to encourage the Philippians in their faith and to provide them with guidance on how to navigate challenges and persecution. His reminder that their citizenship is in heaven serves as a source of hope and perspective in earthly struggles.

5. **Evangelical Interpretation**: From an evangelical perspective, this verse conveys significant theological implications regarding salvation, eschatology (end times), and the believer’s identity in Christ. It reinforces the idea of eternal hope and the transformative power of being a follower of Jesus.

In summary, the Apostle Paul is recognized as the author of Philippians, and from an evangelical perspective, his writing in Philippians 3:20 emphasizes the believer’s heavenly identity and the anticipation of Christ’s return.