The Book of Philippians is in the Bible's New Testament. Paul wrote this letter to the church at Philippi, which he had established (Acts 16:11-40).
Paul was a prisoner when he wrote the book of Philippians. But he used his time in prison well. He even told his guards about Jesus (Philippians 1:13). And he was glad that people were speaking about Jesus (Philippians 1:12-30).
Paul encouraged the Christians in Philippi to work together (Philippians 1:27). They should love each other (Philippians 2:1-4). So, they should be humble. Paul reminded them that Jesus was very humble. (Philippians 2:5-11). But now, God gives great honour to Jesus.
Paul warned the Christians about some people who did not know Jesus (Philippians 3:1-4, Philippians 3:17-19). He wanted the Christians to trust God more. Even Paul himself wanted to know God better (Philippians 3:10-11). Paul did not pretend that he was already perfect (Philippians 3:12). But he knew that God will change us totally (Philippians 3:21). So, we should be glad (Philippians 4:4). We should do the right things (Philippians 4:8-9). And we should trust God to provide whatever we need (Philippians 4:10-19).