Chapter and verse divisions were not part of the original biblical writings. These were added much later to make finding specific passages in the text easier. This verse exemplifies the quirks that modern chapters and verses can create. Philippians 4:1 concludes the thoughts from the last verses of chapter 3.
Here, Paul offers several encouragements to his readers. First, he notes his love for them. Love is a topic mentioned many times in this letter (Philippians 1:9, 16; 2:1, 2; 4:8). Second, Paul mentions his sincere desire to visit them. He had lived among them in the past and missed them now while he was under house arrest in Rome. Third, he calls them "my joy," another theme common in this message (Philippians 1:4, 25; 2:2, 29). Fourth, Paul refers to the Philippian believers as his "crown." These believers were a reward and blessing to Paul.
Paul concludes this section from chapter 3 with a powerful exhortation, urging his readers to 'stand firm thus in the Lord, my beloved.' This call to steadfastness is a recurring theme in Paul's teachings (1 Corinthians 16:13; 2 Corinthians 1:24; Galatians 5:1; Ephesians 6:13; 2 Thessalonians 2:15), emphasizing the importance of resilience and unwavering faith, especially in the face of adversity. His ultimate goal was for his readers to not only endure but to thrive, even in the most challenging of circumstances.