In Philippians 2:12-13, we read something that should give Christians great confidence, “work out your own salvation with fear and trembling, for it is God who works in you both to will and do for His good pleasure.” We are not alone in our efforts to “work out [our] own salvation.” There is power from God.
In Ephesians 1:15-23, this power is something Paul wanted Christians to know. This “power toward us” is “according to the working of His mighty power which He worked in Christ when he raised Him from the dead and seated Him at His right hand…” (Eph. 1:19-20). The power available to Christians is related to the power demonstrated in the resurrection and exaltation of Jesus. It is the same power that is necessary to forgive sin and renew the sinner! (Eph. 2:1-6; Col. 2:11-13).
In Ephesians 3:14-21, this power is described more by Paul. According to Ephesians 3:16, the source of this power is God’s “Spirit in the inner man” (v. 16; Phil. 2:13), but first notice in Ephesians 3:16-17 that he prays that they might “be strengthened with might [power].” Here, Paul used the same word to describe the gospel in Romans 1:16-17 because it is “the POWER of God to salvation.” If we are strengthened with “power,” then, we can conclude that Paul was praying that these brethren might be strengthened “in the inward man” by the POWER of the GOSPEL provided “through His Spirit.” It is “through faith” that Christians are “strengthened with might through His Spirit” (vs. 16). Paul wrote that “faith comes by hearing the word of God” (Rom. 10:17). Therefore, all of the strength and power that the Spirit provides comes from the word of God living in our hearts and minds (Rom. 8:1-11; especially verse 2; 1 Thess. 2:13).
As suggested by Ephesians 3:16, the purpose of this power is to provide “strength.” It is for the purpose of “[working] out your own salvation” (Phil. 2:12-13); to “put to death the deeds of the body” (Rom. 8:12-13); to “glorify God in your body” (1 Cor. 6:19-20). In other words, to “do” what is necessary to please God, but notice carefully in the text (Phil. 2:13), that God “works in you both to will and to do.” The ultimate demonstration of God’s power is seen when we conform our “will” (intent, wishes, and desires) and work (life and conduct) to please Him.