Sanctification by the law – where is that found?

I’ve looked and looked and don’t find any New Covenant context teaching telling us to go back to Moses. Everything I have found shows me otherwise.
Take Romans 12, for example. First chapter after a bunch of theology, including a bunch of “law” talk. Much encouragement for the saints to walk a certain way and not a hint of law-keeping, other than the exhortation to not take vengeance but leave that to God.
What we see is a continual teaching to live by the grace of God, be transformed by renewing your mind, be humble. In the section on body-life Paul tells us how to love one another with specific teachings – but no law-keeping.
Here’s the bottom line: The Mosaic Law and other laws like it (found in many Fundamental fellowships) are intended for those who are unregenerate. What we are taught in Romans 12 is fit only for those indwelt by the Holy Spirit, who wills and equips us to do what pleases the Father.
While all Scripture is for our edification and benefit, the law of the Old Covenant was for those in that covenant. The Law of Moses does not and never has bound people outside that covenant community.
If you are in Christ, there is a better law, fit for a spiritual people. We have a covenant built on better promises, mediated by a better priest, with a new law meant only for the saints.
Rejoice! God’s grace was sufficient to save you and by it He is sufficient to renew your mind and sanctify your soul until Christ returns or He takes you home.