Paul writes Philippians
Philippians 1:12–26; 2:25–30; 4:10–22
Thanking the Philippians for a gift brought by Epaphroditus, Paul wrote from prison a letter full of joy, urging them to have the mind of Christ, who humbled himself to death on a cross and was highly exalted.
I can do all things through Christ who strengthens me.
Philippians 4:13 (World English Bible)
Paul told them that for him to live is Christ, and to die is gain (Philippians 1:21), and that he had learned to be content in every circumstance. Epaphroditus had nearly died of illness while serving Paul.
Dating notes
About AD 61–62, near the end of the Roman imprisonment. Ussher: AD 64. The date is an estimate; Scripture doesn't say when the book was written.