These surprising sentences follow hard on the heels of verse 14, directly modifying most of the brothers [and sisters] (literally, "some, on the one hand, . . . others, on the other hand"). They describe two kinds of evangel-ism, in terms of motivation, taking place in Rome in response to Paul's imprisonment. They are surprising in part because nothing in verse 14 prepared us for this, and in part because of Paul's description of the second group and his attitude toward them. The description itself is set forth in a nearly perfect chiasmus (ABB' A' pattern):
A Some preach Christ because of envy and rivalry (v. 15)
B Others out of goodwill (v. 15)
B' The latter do so in love because they know my imprisonment is on behalf of the gospel (v. 16)
A' The former proclaim Christ out of selfish ambition, not sincerely, supposing they are causing affliction in my bonds (v. 17)
The emphasis lies with the A/A' clauses, with those who are trying to inflict suffering on Paul. But even though it smarts personally, Paul will have none of it—the supposed affliction, that is. Rather (v. 18), he rejoices because Christ is proclaimed on all sides; for him "to live is Christ" (v. 21), hence his ability to rejoice.
Evangelism is now expressed in terms of "preaching Christ." The pure motive of some who do so is goodwill and love, meaning love for Paul. They see that Paul can no longer be involved in preaching Christ publicly, so they have stepped in to pick up the slack. Among these we should probably number those whom Paul greets in Romans 16:3-16, many of whom he there applauds for their "hard work in the Lord."
Along with Paul himself, they understand his imprisonment to be appointed by God: I am put here for the defense of the gospel, words that echo verse 7 and anticipate the (apparent) tribunal referred to in verses 19-20. Thus these friends among the Roman house churches see their role as filling the gap—with regard to evangelism—for a wounded comrade in arms, as it were, who has been divinely appointed to defend the gospel at the highest level of the empire.
This surely reflects the heart of Paul's understanding of his ordeal. From the Roman point of view, Paul is on trial over a matter of religio licita (whether Christians are still under the banner of Judaism), or perhaps of maiestas ("treason"—because they proclaimed another than Caesar to be Lord?—see Acts 17:7). From Paul's own point of view, the gospel itself is on trial, and his imprisonment is a divinely appointed defense of the gospel at the highest echelons.That is exactly where the others have got it wrong. Their preaching of Christ is predicated on envy and rivalry and selfish ambition, aiming at gain for themselves in a personal battle against Paul. They are therefore preaching Christ, but from false motives. They suppose, incorrectly, that they will stir up trouble (thlipsis; cf. 4:14) for me while I am in chains. They think in terms of Paul, his imprisonment and his affliction; he thinks in terms of the gospel, for whose defense he has been appointed. Hence although they are probably something of an annoyance, they cannot really get at Paul; even their "impurity" (v. 18; NIV false motives), Paul recognizes, still advances the gospel!
Our dilemma is how to square his attitude toward these people with what he says elsewhere about those who oppose him and his gospel. The key probably lies with the two words translated rivalry and selfish ambition (eris and eritheia), especially since the latter term, which is infrequent in Paul's writings, appears again in 2:3, where he is urging a united mindset among the Philippians. The fact that these people are preaching Christ, but do so hoping both to afflict Paul and to gain personal advantage over him, means that they cannot be preaching a rival gospel—against which Paul inveighs so strongly in 3:1-3. Therefore they must be fellow believers, but those who have personal animosity toward the apostle.
The best guess as to who these people might be is to be found in Paul's letter to the Romans, where he is concerned about Jew and Gentile forming one people of God as they "follow Christ Jesus, so that with one heart and mouth you may glorify the God and Father of our Lord Jesus Christ" (Rom 15:5-6). That letter in effect tried to do two things: to get Jewish Christians to see how Christ brought an end to the law as a means of relating to God, and to get the Gentiles to moderate their behavior toward the Jewish believers on matters that did not count. Hence most of the letter is written from the perspective of his being an apostle to the Gentiles, trying to show that Christ and the Spirit have brought an end to the significance of Jewish boundary markers; yet the sections of exhortation, especially 14:1—15:13, are written from the perspective of the Gentiles with regard to their acceptance of Jews.
Despite Paul's insistence that the gospel is "for the Jew first" and his affirmations about Christ's being in continuity with things Jewish (Rom 9:3-5; 10:4; etc.), he also says enough things to make Jewish Christians anxious about his way of expressing the gospel. If so, then Romans was effective only in part. Our passage suggests that some of the Roman believers took considerable exception to Paul.
Even though Paul would disagree with these people's understanding of what Christ has accomplished, the difference between what Paul says of them here and what he says elsewhere can be attributed to two factors. First, in every other case (2 Cor 10—12; Gal; Phil 3) where Paul speaks strongly against Jewish Christian opponents, they are trying to convert his churches ("his" in the sense that he founded them and has apostolic responsibility toward them) to their way of understanding Christ. In the present case, of course, the church in Rome is not his own in either sense just noted. Second, the clear difference between this passage and the others is that here his opponents are evangelizing, proclaiming Christ to others (probably fellow Jews) who have not yet believed in him. The others are itinerants involved in "sheep stealing" pure and simple. For them Paul has only anathemas.
Very likely the reason for Paul's including these words here is related to a situation of internal unrest in Philippi. As Paul now writes to Philippi, he does so in light of the local situation in Rome. In 1:27 he exhorts the Philippians to contend for the gospel in one Spirit as one person; in 2:3 he urges that they "do nothing out of selfish ambition"; in 2:13 he reminds them that God is at work in them "to will and to act" for the sake of his goodwill; and in 2:21 he remembers again that some "look out for [their] own interests, not those of Jesus Christ." It seems reasonable to suppose that some strife on the local scene has heightened Paul's concern for the situation in Philippi. Thus with verses 15-17 he anticipates the exhortations of 1:27—2:16 and 4:2-3.