Even when people realize that they should obey God and His commands, they may still scratch their heads over why obedience is necessary to the salvation process. If we are saved by grace through faith—as Ephesians 2:8 makes obvious—and not justified by works of lawkeeping (Galatians 2:16), what good do they do? Is not obedience to God's law useless or at the best, merely dutiful or ceremonial?
Those who ask these kinds of questions have a limited understanding of what God is doing with humanity. In essence, they believe that God's sole purpose is to "save" people from their sins, for that is what Christ's sacrifice accomplishes—the shedding of His precious blood pays the penalty for sin, redeeming us from eternal death, and with His righteousness covering our corruption, provides us access to a relationship with the Father (see Romans 5:6-11). This is a wonderful, divine act of grace because we do not deserve such merciful treatment.
The truth is, however, that salvation does not end there. One of the apostle Paul's comments in Romans 5 hints broadly at this: "Much more, having been reconciled [to the Father], we shall be saved by His life" (verse 10). Christ's death does not save us, but His resurrection to eternal life does! Not only does it make possible our future resurrection to eternal life (see I Corinthians 15:20-23), but it also allows Him to work with those whom God calls to bring them to spiritual maturity. Notice how Paul describes Christ's ongoing work with the church:
And He Himself gave some to be apostles, some prophets, some evangelists, and some pastors and teachers, for the equipping of the saints for the work of ministry, for the edifying of the body of Christ, till we all come to the unity of the faith and of the knowledge of the Son of God, to a perfect man, to the measure of the stature of the fullness of Christ. (Ephesians 4:11-13)
As Head of the church (Ephesians 1:22-23; Colossians 1:18), Christ now works to bring us "to a perfect man," that is, He is completing a spiritual process to fashion us in His own image. Paul calls this "the new man" in Ephesians 4:22-24: "Put off, concerning your former conduct, the old man which grows corrupt according to the deceitful lusts, and be renewed in the spirit of your mind, and that you put on the new man which was created according to God, in true righteousness and holiness." Theologically, this process is called "sanctification."
This is where our obedience comes into play. Paul writes in Hebrews 5:9, "Having been perfected, [Christ] became the author of eternal salvation to all who obey Him." Keeping God's commandments—His instructions—will guide us in learning what God requires of us and in impressing His character image upon us. God's laws do not save us, but they provide a pattern of behavior that pleases Him because such behavior reflects His own. Obedience, then, becomes a tool that we use in conjunction with Christ to grow in righteousness and prepare for the Kingdom of God.