Christ is being preached, by Paul's life and by his death, by others responding to Paul's absence some in contention some in love, by the churches outreach and operation even under extreme persecution. Some would think that they have the upper hand but, who has the upper hand over God? Is this not how He said it would be? Is this not a necessary part of our sanctification to share in His sufferings? Is He not sovereign and in complete control? Has any one or anything snuck up on Him that he had mistakenly underestimated or poorly considered? Of course not, for Christ is preached!
There is the eternal salvation direct from our confession and repentance acknowledging Jesus Christ as Lord, the salvation that because of His sacrifice was purchased and imputed to us. There is also the salvation having the knowledge of Jesus Christ that we are fruitful with as applied toward our daily circumstances and situations; this is the type of salvation that we work out. One can be saved in the one sense but yet be a poor worker of the salvation that effects daily life, even by the things in this same chapter Paul speaks to, contention and strife and isolation from the broader body etc..
Paul has returned Epaphroditus to the brethren in Philippi to cheer this congregation up. Paul is also about to send Timothy his prize student to strengthen them. In his letters Paul seems to make everything even general matters as a teaching opportunity. We also see that Paul could only trust certain people for certain types of missions. Paul not only thought of who needed help but who it was that he was sending.
Pressing toward the mark, not that we have already attained perfection; having no other confidence but in Christ, the fellowship of His death and sufferings that we may know the power of His resurection. How different this sacrifice/pursuit is from mere religion.