Phil 3:9

3:9 not having a righteousness of my own. Paul now recognizes that salvation is based not upon human attainments of obedience to the law, but entirely and exclusively upon “the righteousness from God,” given to those united with Christ (Rom. 1:16, 17; 3:21–26).

faith in Christ. Christ is the object of faith (Gal. 2:16), and now that he trusts Christ alone, Paul abandons all reliance on his own credentials (vv. 7, 8). Faith is the instrument, not the ground, of salvation, and Paul declares that we are saved “through faith,” never that we are saved “on account of faith.” The ground of salvation is the merit of Christ. Faith as the instrument does not provide value of its own but links us to Christ and His merit.

depends on faith. Faith receives God’s gift of righteousness (Rom. 3:22; 5:17), and on the ground of this righteousness the verdict of justification is given when a person believes (Rom. 4:3; 5:1; Gal. 3:6). In this way faith and justification occur at the same time, although faith is logically first.