Servants ye are to whom ye obey;
whether of sin unto death,
or of obedience unto righteousness.
Rom 6:16

How about the parts of the law such as: don't eat swine or hare, or bring in your tithes, or perform you oaths to God? These parts of the Law died, for they were only shadows, ceremonies, and forms. These parts of the law are dead to us, but the inward law, the law that is written on every man's heart, his conscience, is alive and to be obeyed. And the inward law is the same as the outward law's moral parts. What is still alive is the core of the law. The core of the law is our schoolmaster, until we are advanced spiritually enough to be led by the Spirit of God.

The core, or inward parts, of God's Law were explained partially when Jesus answered the question:

Master, which is the great commandment in the law?
Jesus said unto him, Thou shall love the Lord thy God with all thy heart, and with all thy soul, and with all thy mind.
This is the first and great commandment.
And the second is like unto it, Thou shall love thy neighbor as thyself.
On these two commandments hang all the law and the prophets. Matthew 22:35-42

Further clues from Jesus were: Go and learn the meaning of this: I desire mercy, not sacrifice. Mat 12:7.
Meaning outward sacrifices are not what he wants, he wants you to forgive and love your neighbor.

Woe unto you, scribes and Pharisees, hypocrites! for ye pay tithe of mint and anise and cumin,
and have omitted the weightier matters of the law, judgment, mercy, and faith:
these ought ye to have done, and not to leave the other undone.
Ye blind guides, which strain at a gnat, and swallow a camel. Matthew 23:23-2

Why do Your disciples not order their way of living .. eat with hands unwashed and ceremonially not purified?
..These people honor Me with their lips, but their hearts hold off and are far distant from Me.
In vain .. do they worship Me, ordering and teaching as doctrines the commandments and precepts of men. Mark 7:5-7

Forget about food, drink, washing properly; for whatever enters the mouth goes into the stomach and then out of the body?
But the things that come out of the mouth come from the heart, and these make a man 'unclean'.
For out of the heart come evil thoughts, murder, adultery, sexual immorality, theft, false testimony, slander.
These are what make a man 'unclean'; Mat 15:18-20

So Jesus is telling people the important part of the law is love, mercy, and faith. At the same time, he is telling us that the tithing, sacrifices, and ceremonies are not important. He is stressing the inward condition of a man's heart - whether it is filled with love and mercy or evil.

Paul tells us: for not the hearers of the law are just in the sight of God,
but the doers of the law will be justified; [permanently]
for when Gentiles, who do not have the law, by nature do the things in the law,
these, although not having the law, are a law to themselves,
who show the work of the law written in their hearts, their conscience also bearing witness,
and between themselves their thoughts accusing or else excusing them. Rom 2:13-16

So all men already have an inward moral law written in their hearts, and it is to be obeyed;
the law is not to be ignored because we believe in Jesus, who supposedly excuses us from all requirements to obey the Law.
But Paul says: Only the doers of the law will be justified.