What does Philippians 1:17 mean?

Paul referred to those properly motivated to preach Christ in verse 16. In verse 17, his thoughts return to those with inappropriate motivations. Their goals were selfish, jealous, and even hostile. Some might have even spoken about the gospel for the purpose of making Paul's imprisonment worse. Such people were more concerned with their own benefit than the spread of the gospel.

However, the opposite was actually the result. First, their selfish ambition led to more people hearing about Jesus. Second, the growing popularity of Christianity may have had something to do with Paul's later release. The church was small when Romans was written in 55–56. Yet by 64, less than 10 years later, Christians had become a large enough minority to receive the blame from Nero for the fires in Rome. Believers endured intense persecution during this time, traditionally including the deaths of both Paul and Peter in or near Rome during Nero's reign (AD 64–68). Both the Gospels of Mark and Luke may have been written in Rome during this time period as well.

Truth is a powerful thing; the harder one tries to suppress it, the more eagerly it seems to spread!