“Only let your conversation be as it becometh the gospel of Christ: that whether I come and see you, or else be absent, I may hear of your affairs, that ye stand fast in one spirit, with one mind striving together for the faith of the gospel” (Phil. 1:27).
Interestingly, whenever Paul uses the phrase “stand fast,” it is always to challenge people to stand fast in an area in which they were not standing fast! For instance, he tells the Corinthians to “stand fast in the faith” (I Cor. 16:13), for they had lost their faith in one of the fundamentals of the faith, the resurrection (I Cor. 15:12-50). He told the Galatians to “stand fast in the liberty wherewith Christ hath made us free” (Gal. 5:1) because they were forsaking grace for the law. He told the Thessalonians to “stand fast, and hold the traditions which ye have been taught” (II Thes. 2:15), especially the “tradition” of working for a living (3:7-12). The Thessalonians had become so excited about the Rapture that many of them quit their jobs in anticipation of the Lord’s coming!
But here in Philippians 1:27, Paul tells the Philippians to “stand fast in one spirit, with one mind striving together for the faith of the gospel.” This is because two ladies in the church were quarreling (4:2), and some in the church were siding with Euodias and some with Syntyche. “Striving together” is the Greek word sunathleo. The prefix sun means together with, and athleo is the word from which we get athlete and athletics. Athletes are often teammates who must strive together to achieve a common victory, and this is what Paul was calling on the Philippians to do for the cause of Christ.
Notice Paul isn’t talking about faith in the gospel. The faith of the gospel is our faithfulness or fidelity to maintaining the gospel as God gave it, just as old “high-fi” or “high-fidelity” records claimed to be highly faithful to the sound recorded in the studio. We are to strive together to maintain fidelity to the gospel God gave to Paul.
Finally, Paul does not say we should strive with one another for the faith of the gospel. He rather says we should be striving “together” as those who see the fellowship of the mystery with those who don’t. With all the talk about “peace on earth”, how refreshing it would be if we could enjoy the “conversation peace” Paul longed to see in Philippi! (Psa. 133:1; Eph. 4:3). source