Paul’s second reason for joyful thankfulness to God is his confidence that God will complete the good work he has begun in the Philippians (v. 6). This work, which must be identified with the Philippians’ salvation, will reach its consummation only at “the day of Christ Jesus.” It is a work that God alone accomplishes, but the notion that it is not yet complete shows that it involves a progressive transformation of the lives of believers. The “good work” of salvation, then, includes God’s gift to believers both of the will and of the ability to do good works. The presence of these good works in turn provides evidence of real belief—evidence that God has begun and will complete the work of salvation in the person who displays them. Thus Paul says in 1:28 that the Philippians’ steadfastness in the midst of persecution serves as a sign of their future salvation, and in 2:12–13 that whereas the Philippians should “work out” their “salvation with fear and trembling,” God is the effective power behind this work. This thought also lies behind Paul’s confession in 3:12, that he presses on “to take hold of that for which Christ Jesus took hold of me.” It is only because God in his grace has taken hold of believers and works within them to produce a life consistent with the gospel that they can in any sense “take hold” of salvation on “the day of Christ Jesus.” In other words, those who will be saved in the future live holy lives in the present, but the holiness that characterizes their lives is God’s work from beginning to end.

If this represents a correct understanding of verse 6, then Paul’s first two reasons for joyful thanks to God are probably bound to one another by a profound theological truth. Paul thanks God for the Philippians’ partnership in the gospel not only because of the practical assistance it provided for the advancement of the gospel but also because it stands as a confirmation that God is at work in the lives of the Philippians (cf. 4:17). Paul knows, moreover, that if God has begun a work of grace in the Philippians, he will complete it, for he has the power “to bring everything under his control” (3:21); he is thus confident that God will conduct the Philippians safely into the realm of salvation on the day of Christ Jesus. This, he feels, is reason enough to rejoice.