2:12 Therefore. On the basis of Christ’s supreme example, Paul resumes his appeal. The apostle’s presence encourages the Philippians to obey, but the basic motivation is from “God who works” in them (v. 13), and their obedience will flourish in Paul’s absence as well (1:27).
your own salvation. As in 1:28, this is salvation in the full, redemptive sense with particular stress on the sanctification of the believer. The sanctifying process calls for obedience to the exhortation of vv. 1–5. See “Sanctification: The Spirit and the Flesh” at 1 Cor. 6:11.
fear and trembling. This is awe and reverence rather than panic and alarm. The right emotions are stirred by the presence of God (v. 13), and not by questions or doubts about eternal security.