4:4 Rejoice in the Lord always. I will say again, rejoice!
This verse hearkens back to 3:1, which might as easily have started a conclusion to the letter. As we mentioned, the unexpected sidebar into Paul's Jewish credentials have led some to most of chapter 3 as an insert from another letter to the Philippians, especially since Ignatius seems to know of more than one. However, we do not seem to have an adequate basis to conclude this way, so it is best to assume that chapter 3 was part of this letter and any other letters are lost to history. Further, 4:4 would be redundant if it followed right on 3:1.
The theme of rejoicing would seem to be one of the major themes of Philippians, along with unity. As we will mention more than once as we look at the verses that follow, Paul's theme of rejoicing is all the more significant given that he is in prison possibly facing death as he writes.
4:5-6 Let your gentleness be known to all persons. Don't be anxious about anything, but in everything, with prayer and request with thanksgiving, let each make known your petitions to God.
Since the core ethic of the faith is love, a Christian should be gentle and harmless to others. This should be something for which they are known.
At the same time, they should have the kind of surrender to God's will that defuses anxiousness. This is a again a theme that will reappear in a few verses. Faith in God's love and proper honor to God, leave no reason for anxiousness as the Philippians make their needs known to God.
4:7 And the peace of God that surpasses all understanding will guard your hearts and thoughts in Christ Jesus.
The result is peace, in the opposite category of anxiousness. One might understand a situation and accordingly be anxious about it. But trust in God yields a peace that passes all understanding. Perhaps what Paul more precisely has in mind is that the peace is beyond comprenhension, a mysterious peace. That peace should typify the Philippians' experience of life, even in hardship, like a guard protecting them.
4:8 The rest, brothers, whatever things are true, whatever are honorable, whatever just, whatever pure, whatever lovely, whatever of good report, if something is virtue and if something is praise--be thinking about these things.
Paul begins the end of these miscellaneous exhorations with a virtue list of sorts. As always, it is not an absolute list but a loose collection of good things. Anxiousness and hatefulness are not the kinds of things on which one should focus his or her mind, but good things.
Truth is an appropriate focus of thought, not lying or falsehoods. Things that are honorable, virtuous, and of good report are worthy of thought, not shameful or hidden vices. There the honor-shame dynamic of ancient culture shows through. There seems to be an assumption that core values are generally understood by all, only not practiced.
Justice and righteousness are things to think about, not getting ahead by cheating or taking advantage of others. The pure and the lovely, the beautiful, these line up with godly thought. A life of thought focused on such things is a life focused on virtue.
4:9 Also be practicing the things that you learned and received and heard and saw in me. And the God of peace will be with you.
In addition to these common values, things generally understood to be good even by non-Jews, there are the specific Christian instructions Paul has given the Philippians. It is tempting, although anachronistic, to distinguish verse 8 from 9 along the lines of natural revelation and special revelation. Perhaps there is some basic truth to the division.
Beyond common virtue are specifically Christian understandings of what to believe and how to live. Paul assumes that the Philippians are specifically under his authority. He does not tell them to obey Peter or Jerusalem, but his teaching and example. If they will do all these things, then they will be at peace.
The recurrence of language of peace in this section suggests that the Philippians might have cause to be anxious. Presumably they are anxious over Paul's fate. And they are presumably anxious over the health of Epaphroditus. Perhaps they are also anxious about the political fate of themselves as believers. Paul has been thrown into prison and potentially faced death because of his actions as a believer. Would they eventually face the same fate?
But God is a God of peace, a kind of peace that is surprising and incomprehensible given such circumstances.