The church lives under the law of Christ!
Do you know what that means? What do you suppose is different about the law of Christ than the law of Moses, since we know from scripture that we do not nullify, but uphold the law of Moses? The difference is Christ does need a law about what to do when he sins. Neither do we. Not because the law of Moses was cast down and destroyed. But because Christ and his body (us) don't need laws to instruct us how to atone for sin. In our case
that's already been done for us. Those laws are still the law of Moses but those laws just aren't needed anymore for believers. They have been fulfilled, not removed from the law.
What remains to be kept by us are laws summed up in the one law 'love your neighbor as yourself'. That is the law of Christ. The law of Christ is not a new law. It's the law of Moses minus the laws governing payment for sin and various other things that have already been done for us through our faith in Christ.
If anything from the old was RE-established for the church, then it is a command for the church that is found in both. But make no mistake we do nothing to follow the Mosaic Law.
James and Paul both disagree with you.
James 2:8
8If you really keep the royal law found in Scripture, “Love your neighbor as yourself,” a you are doing right. 9But if you show favoritism, you sin and are convicted by the law as lawbreakers.
1 Corinthians 14:34
Women are to be silent in the churches. They are not permitted to speak, but must be in submission, as the law says.
Romans 3:31
31Do we, then, nullify the law by this faith? Certainly not! Instead, we uphold the law.
Why are they making an appeal to the law if it is as you say that it is gone and done away with and non-existent now? The law
as a covenant is what is gone now. Don't confuse the two.
Example. California and Massachusetts both have 65mph speed limits on their highway. When I am in Massachusetts, I drive 65MPH not because California (the Mosaic LAw) says to drive 65 but because Mass. (the law of christ) says to drive 65.
Here's a better analogy. Driving a new electric car doesn't cast down and remove laws requiring you to pass gasoline engine emissions requirements. They remain but you simply don't need them anymore. And so they are set aside for you as obsolete and not needed now, not removed from the law. But owning an electric car does not relieve you of satisfying the lawful requirement for you drive 55 MPH (or whatever the speed limit is) and to stop at stop signs out of concern for the safety of yourself and others. Your electric car didn't relieve you of your obligation to obey those laws.
Our old selves are like cars powered by gasoline that require laws to maintain and correct the output of the dirty emissions they emit. Our new selves are like cars powered by electric (think Holy Spirit) that don't require laws to deal with dirty emissions, not because those cars are allowed to break those laws, but because those dirty emissions
have already been taken care of for us and so those laws simply don't apply to us. They have been set aside as unneeded for us,
not erased from the law. And so the law governing the output of emissions is marked 'satisfied' for us. God....I mean, the Dept. of Transportation.....looks at our electric car and says, "I see no violation of emission laws here". And so the law of emissions is
satisfied, not removed out of the law, and certainly not allowed to be broken by us.
Even though all this is true, we are still required to drive our cars according to the rules governing how to drive your car. Those laws didn't get fulfilled for us by owning an electric car. We have to keep those ourselves. But even then we're doing that in the power and efficiency of our new electric car. And that's how it is in regard to our new 'cars' and the law of Moses. Our new lives in Christ don't remove the law of Moses, it upholds it. ALL of it. It doesn't erase any law, or get replaced by a different law.
If you read this, thank you for taking the time to read it.