Philippians 1:28 “And in nothing terrified by your adversaries: which is to them an evident token of perdition, but to you of salvation, and that of God.”
For the word “terrified” this is the only use in the New Testament for this kind of fear. This fear is like horses scared into a stampede. When threatened we need to stand fast in God’s grace. Our resistance to their opposition is a token to them that they have lost already. When Paul says “your adversaires” he means the tools (people) of our adversary (Satan), see 1 Peter 5:8. And the “evident token” is Christians showing salvation through Jesus Christ by our good behavior towards them in spite of what comes our way.