What does Philippians 1:24 mean?

Paul has been musing about the conflict he feels at this time of imprisonment. Which does he want more, to endure persecution and preach the gospel, or to be taken to eternity with Christ? Paul concludes that, since God's will is for others to be saved, it is better for him to be alive. When God wills Paul's death, it will happen. Paul's focus must be to stay alive and serve others, including the Philippian believers. In fact, Paul seems to have a special burden for believers such as the Philippians; his comment here specifically mentions the readers of this letter as a reason for him to live on.

In Colossians 4:3 Paul will add a related note: "the mystery of Christ, on account of which I am in prison." Paul was imprisoned because of following Christ. He wasn't there for personal failures, or for something random. There was a God-given reason for it, though that didn't make it any easier to endure. The benefit of this persecution included the evangelism of many people in Rome, as well as influence through writing four Prison Epistles.