NOTE: This is a condensed excerpt from my forthcoming (2014) commentary on Philippians.
Paul identifies two groups in Rome who have been emboldened in their preaching of Christ because of his faithful witness while under house arrest. In the first group are those who do so from envy and rivalry, or perhaps better “because of envy and rivalry.” Paul combines these two terms elsewhere to describe what life ruled by the flesh looks like (Rom 1:29; Gal 5:20-21; 1 Tim 6:4), a clear indictment of these particular believers. The Greek word translated envy (phthonos) refers to “a state of ill will toward someone because of some real or presumed advantage experienced by such a person”; it is “concerned more to deprive the other man of the desired thing than to gain it.” The same expression occurs in Mark 15:10 to indicate the motives that led the chief priests to hand Jesus over to Pilate. In this context the envy of some who are now preaching Christ could stem from any number of things, including but not limited to: Paul’s recognized status as a leading figure, Paul’s obvious success, or even his notoriety for being a troublemaker. The Greek word translated rivalry (eris) is more difficult to translate; it refers to “conflict resulting from rivalry and discord.” Thus although the word generally means conflict, the context here suggests the more specific sense of rivalry. These brothers are interested in establishing themselves and their ministries in competition with Paul; they are more interested in the expansion of their own ministries than the spread of the gospel per se.
In contrast to the first group of brothers, the second preach Christ from good will. While the Greek word eudokia can mean a basic good disposition, the context here suggests the stronger sense of the word that indicates “pleasure.” That is clearly the sense of the word in Phil 2:13, and it fits the context here. Thus the point is not merely that these brothers preach Christ from good rather than bad motives. It is rather that these brothers preach Christ because they are motivated by a deep and satisfying delight in the Christ they preach.
People preach the gospel for a variety of reasons. Some see it as the path to fortune and fame, preeminence and prestige. More subtly, some preach Christ with one eye on the gospel and another on others engaged in ministry, falling into the subtle but deadly trap of comparing the results. Still others preach Christ because he is their greatest delight. Why do you preach Christ?
 The Greek preposition dia when used with the accusative case often indicates the cause of something (BDAG B.2.a), as it does here.
 This combination is also found in Philo, where he lists these vices among those things that oppose happiness (Mut. 1:95).
 LN 88.160. An interesting parallel is found in the Greek comic poet Philemon (ca. 362– ca. 262 B.C.), who lamented “You abundantly teach me many things because of envy” (cited in VGNT, 667). Doubtful is the suggestion of Bruce Winter, who attempts to connect this word to the political realm and an effort to cause Paul difficulties at his trial; see Bruce W. Winter, Seek the Welfare of the City: Christians as Benefactors and Citizens (Grand Rapids: Eerdmans, 1994), 93-94.
 NIDNTT 1:557. The entry goes on to quote the Greek writer Xenophon: “The envious are those who are annoyed only at their friends’ successes.”
 LN 39.22. All nine NT occurrences are in Paul (Rom 1:29; 13:13; 1 Cor 1:11; 3:3; 2 Cor 12:20; Gal 5:20; Phil 1:15; 1 Tim 6:4; Titus 3:9), and all but two (1 Cor 1:11; 3:3) are in vice lists. According to Philo, eris is the “mother of anger” (Leg. 3:131) and “the most grievous of diseases” (Imm. 1:97).
 For more on the identity of these “preachers,” see discussion at 1:17 and the Introduction.
 BDAG 1; so also commentators such as Fee, Philippians, 120; Hansen, Philippians, 72; Witherington, Philippians, 81.