Note 23 at Phil. 1:28: The word "terrified" in the Greek is a strong term referring to the shying away of a horse that has been startled. The "adversaries" who caused this fear were unbelievers who showed hatred and hostility to the Philippian believers. So, Paul is speaking of persecution against the Philippian believers. The persecution these adversaries brought against the Philippians was a token that the persecutors were headed for perdition (see ref. r at this verse). If they were true believers, they would not be fighting their own.

On the other hand, to those who are the persecuted, persecution is a token that they are truly born again. Jesus taught that godly people would be persecuted (Mt. 5:10-12) and so did Paul (2 Tim. 3:12). The fact that these believers were being persecuted confirmed their salvation and at the same time revealed their persecutors as being enemies of Christ with the result of eternal perdition.

The suffering of persecution is not an indication of divine disapproval but rather a sign of true adoption into the family of God. For we are called, not only to believe in Christ, but also to suffer for His sake (v. 29). The Philippians were experiencing the same type of persecution that Paul was going through (v. 30). Paul is stating to the Philippian believers that they were in this fight together and should therefore receive encouragement and strength from each other.