Romans 6:14
For sin shall not have dominion over you, for you are not under law but under grace.

This is a scripture well known and quoted in Christendom – you are not under law but under grace.
The Mosaic Law is introduced to show exactly what sin is, even in the smallest actions of life.
No one could ever totally keep the Law and failing in just one point of the Law made you guilty of violating the entire Law.
Jesus came, perfectly living under the Law, and died for the rest of us, who could not keep the Law.
Now sin shall not have dominion over, not because the Law is dismissed, but because the Law is fulfilled in Christ.
We are not under the Law because we already know we are sinful and find ourselves living under grace where sin is cleansed by the Blood of Jesus.
What the Law could not do through its requirements, Chris did through His obedience.
So is it necessary to live under the Law?
It is necessary to live under Christ and by the law written on our hearts rather than on tablets of stone.
Can you follow the Law any better under Christ than you die before Christ?
No.
Then why try, for you are not under law but under grace.
Now live like you are under grace!