Philippians 1:27-30 (ESV)
27 Only let your manner of life be worthy[a] of the gospel of Christ, so that whether I come and see you or am absent, I may hear of you that you are standing firm in one spirit, with one mind striving side by side for the faith of the gospel, 28 and not frightened in anything by your opponents. This is a clear sign to them of their destruction, but of your salvation, and that from God. 29 For it has been granted to you that for the sake of Christ you should not only believe in him but also suffer for his sake, 30 engaged in the same conflict that you saw I had and now hear that I still have.
Paul encourages us to live lives that are worthy of the gospel of Christ. Paul knows that this will lead to challenges with other people, because most of the world opposes the gospel. So we are encouraged, “Don’t be frightened,” even if we are to suffer, because we have the assurance of eternal salvation. See also Jesus’ words in Matthew 10:28