Grace and faith are the characteristic features of the present dispensation. Not only is salvation now declared to be by grace, through faith, but the Spirit also operates in the believer by grace, through faith. He does not take possession of us and cause us to do what is right, but dwells within each believer (I Cor. 6:19) to provide needed guidance and the strength to withstand temptation, and we may avail ourselves of this provision by faith.
The Spirit, Who first imparted life to us will also impart strength to withstand temptation and overcome sin. In our inability to even pray as we ought, “the Spirit… helpeth our infirmities” and “maketh intercession for us” (Rom. 8:26). In our weakness we are “strengthened with might by His Spirit in the inner man” (Eph. 3:16) and God even stoops to “quicken [our] mortal bodies by His Spirit that dwelleth in us” (Rom. 8:11).
“Therefore, brethren, we are debtors, not to the flesh, to live after the flesh” (Rom. 8:12).
The implication from the above passage is that though sorely tempted we are debtors to the Spirit who dwells within and provides overcoming power.
The question, in times of temptation, is generally whether we truly desire to overcome, for we may overcome in any given case by grace, through faith. In the present dispensation it is not true that it is not possible for the believer to sin, but it is blessedly true that in any situation it is possible for him not to sin, for the Spirit is always there to help. source