As in most of his letters, and in keeping with the conventions of letter-writing in the Greco-Roman world, Paul concludes with the standard greetings (vv. 21-22)--plus a grace-benediction (v. 23). Despite their diversity, the Pauline greetings have three basic components, all of which occur here in their tersest expression:
1. The imperative to greet all the saints (which is the way he greets each of them).
2. Greetings from his immediate companions.
3. Greetings from other saints in his present location.
Here the only elaboration, and only surprise, is the inclusion of those who belong to Caesar's household in the final greeting. Such greetings are one of the ways Paul kept the various churches aware of and in touch with one another. In their own small way, therefore, they function as part of his concern for the unity of the body of Christ.
On the meaning of "saint(s)" see commentary on 1:1. In saying "every saint," Paul is thus not greeting the community lumped together as a whole but each member of the community individually. He does not single anyone out, but he does greet each of them in this fashion. It is not clear whether in Christ Jesus modifies "every saint" or "give my greetings." The word order would seem to favor the former; but that creates an unusual--and unnecessary--redundancy. To be a saint is to be in fellowship with Christ Jesus. Moreover, this phrase, which is especially frequent in this letter, usually modifies the verb in its sentence (although 4:19 is a notable exception). Most likely, therefore, Paul intends the greeting to be in the name of Christ Jesus. They are thus to pass on Paul's greetings to one another, and the greeting is to be in Christ Jesus, who is both the source and the focus of their common life together.
The next greeting reaches out to the broader circle of believers in Rome. Here he does indeed say all the saints, and he surely intends that, even if many of them do not even know they are being included--and in light of 1:15 and 17 some of those might not wish to be included! But they are all included simply because they all belong to one another, those in Rome to each other and those in Rome to those in Philippi as well.
But in this case Paul adds the intriguing especially those who belong to Caesar's household. Household would include household slaves as well as family members, but in either case it refers in particular to those who actually lived in Nero's palace in Rome (now uncovered by archaeologists and accessible to tourists). Two matters are noteworthy.
First, this little phrase joins with mention of the Praetorian Guard in 1:13 as the strongest kind of evidence for the Roman origins of this letter. Every objection to this takes the form of trying to gainsay a simple historical reality, namely, that both of these groups are especially "at home" in Rome. All other views must seek to discredit the obvious and thereby discount the significance of this notation.
Second, the import of this greeting could hardly be lost on the Philippian believers, whose opposition in part at least stems from the fact that Philippi is a Roman colony, where devotion to Caesar had a long history. Paul and the Philippians have a common source of opposition: they suffer at the hands of Roman citizens loyal to Caesar, Paul as an actual prisoner of Caesar. But by incarcerating him at the heart of the Empire, they have thus brought in a member of the "opposition" who is in the process of creating a "fifth column" within the very walls of the emperor's domicile. Paul either has found or has made disciples of the Lord Jesus among members of the imperial household, who are thus on the Philippians' side in the struggle against those who proclaim Caesar as lord! Paul is an indomitable apostle of Christ Jesus. Let him loose and he will be among those "who turn the world upside-down" (Acts 17:6; a charge of sedition!) for his Christ; imprison him too close to home and he will turn Caesar's household upside-down as well. Here is a word of encouragement. The "word of life" to which the Philippians hold firm (Phil 2:15-16) has already penetrated the heart of the Empire. They have brothers and sisters in Caesar's own household, who are on their side and now send them greetings; and therefore the Savior whom they await (3:20) will gather some from Caesar's household as well as from Caesar's Philippi when he comes.
On this note the letter comes to an end. One hesitates to draw out too much theology from these rather conventional closing formulas. But as noted at the beginning and elsewhere (e.g., 4:8, 11-13, 15-16) in Paul's hand conventions are never merely conventional. Eventually everything, including these conventions, is brought under the influence of Christ and the gospel. Thus the final greetings of Philippians, which by their threefold elaboration presuppose the church as the body of Christ, are to be given and received as in Christ Jesus. And the final grace is also from the Lord Jesus Christ, so that the whole letter, from beginning to end and everywhere in between, focuses on Christ, who as Paul's life (1:21) is magnified both in his language and in the two narratives that point specifically to him (Christ's in 2:5-11 and Paul's in 3:4-14). To miss this central focus on Christ would be to miss the letter altogether, and to miss the heart of Pauline theology. May we who read this letter as the Word of God follow in Paul's train.