This law within our hearts is placed there by God. It will more closely match the true spirit of the law rather than just the letter of the law the religious leaders and the proud boast about. This happens when we trust in Jesus Christ to save us. We ARE saved by the grace of God through faith and not by our works. A genuine faith will show forth in the way we live our lives before God and others. But our works or our obedience to the law does not save us - only faith can do that because we have the righteousness of Christ and not our own. There will be no bragging or prideful boasting in heaven over what we did for God because we got there because of what He did for us.
...” The indwelling Holy Spirit, given as the earnest of our inheritance, spurs our new nature to live in holiness”....
And that is our walk of “faith”. I think it’s relatively easy to imagine that we walk this of our own strength...a walk we cannot do without the Holy Spirits prompting. Too often he is left out of the equation of law and grace when in fact he is the “power” which moves us.
It has been said that the fallen nature loves religion when in fact the gospel is ‘the opposite of religion’. Our former nature loved ‘to do’ the works of the law because it also feeds the great sin of pride and perhaps also to prove to ones vanity ‘worthy’.......however we learn that in doing the walk of faith in our own strength we’re really attempting to reform ourselves rather than inviting his spirit to live his life through us.
This is a hard thing for some to understand as I myself took some time to grasp it.