While I agree that we are under the New Covenant and not the Mosaic Covenant we are nevertheless still under the same God, who attributes are eternal, so therefore God's Law or instructions for how to act in accordance with His attributes is likewise eternal. For example, God's righteousness is eternal (Psalms 119:142), so therefore all of God's righteous laws are likewise eternal (Psalms 119:160), and the same goes for all of God's other attributes. The Mosaic Law was given to instruct how to reflect God's image, how to walk in in ways (Deuteronomy 8:6), and display God's attributes to the world: holiness, righteousness, goodness (Romans 7:12), justice, mercy, faith (Matthew 23:23), and other fruits of the Spirit (Exodus 34:6-7). In Leviticus 11:44-45 refraining from eating unclean animals is part of God's instructions for how to do what is holy for He is holy, or in other words, to act in accordance with His holiness, and these verses are referenced in 1 Peter 1:13-16 where we are told to do what is holy for God is holy. If the way to act in accordance with God's holiness has changed, then God's holiness has changed, but God's holiness is eternal and does not change.
Morality is based off of God's attributes and in regard to what we ought to do. We ought to obey God, so all of God's laws are inherently moral laws and it is always immoral to disobey any of God's commands.
I tried to make the case in my previous post that Jesus did not teach higher standard, but rather than he taught how the Law was originally meant to be understood, but even if you still think that Jesus taught a higher standard, then meeting a higher standard is inherently inclusive of a meeting a lower standard. In other words, you can't meet a higher standard while disregarding things that a part of meeting a lower standard.
This is where it becomes critically important to distinguish between what is said man-made laws and what is said of God's law, because this is using sleight of hand to take examples where Jesus and the disciples did not observe the rules of the Pharisees as saying that they did not observe what God commanded in the OT. In the 1st century, there was a large body of Jewish oral laws, traditions, rulings, and fences that they taught for how to obey the Mosaic Law, which they taught were needed to be obeyed in order to be saved, which would eventually get recorded in the Mishna, and which Jesus referred to as placing a heavy burden on the people (Matthew 23:2-4). Jesus was certainly not criticizing the Pharisees for teaching the people to do what God had commanded them to do.
Pleroo: to fulfil, i.e. to cause God's will (as made known in the law) to be obeyed as it should be, and God's promises (given through the prophets) to receive fulfilment
In Matthew 5:17-19, Jesus said that he came to fulfill the Law and then proceeded to fulfill the Law six times throughout the rest of the chapter by causing God's will as made known in the Law to be obeyed as it should be.
Obedience to God's Law has always been a matter of the heart and God has always disdained outward obedience to His Law while His people's hearts were far from him because that is missing the entire point of obeying the Law. From the beginning with God walking with Adam in the Garden, what God has always wanted is an intimate relationship with us and the goal of His commands is to teach us how to grow in this relationship. In Philippians 3:8, Paul counted outward obedience to the Law without being focused on growing in a intimate relationship with Christ as being rubbish, because it is again missing the entire point. In Romans 9:30 - Romans 10:4, the reason why Israel failed to obtain righteousness was not because they did what God told them to do and God gave them faulty commands, but rather they misunderstood the purpose of the Law and pursued it as though righteousness were by outward works instead of pursuing the Law by faith.
I would love it if you point out where God Law says that we become defiled by eating with unwashed hands because I can assure you that it is not found anywhere in God's Law. In Matthew 15:2-3, it makes a clear contrast between the traditions of the elders and the commands of God, so what is said against obeying the traditions of the elders should not be taken as being against obeying the commands of God. While Jesus and his disciples certainly broke the traditions of the Pharisees in regard to how to keep the Sabbath, they never broke God's command to keep the Sabbath. Jesus made the argument that it was lawful to do good on the Sabbath, so he was not speaking against obeying the Law, but was teaching how to correctly obey it.
John 8:1-12 is example of Jesus following the Law rather than making changes to how it is obeyed. There was no judge to pronounce a sentence (
Deuteronomy 19:17-21), there was no man accused (
Leviticus 20:10), he didn't have any witnesses to examine (
Numbers 35:30,
Deuteronomy 19:5), and he did not have a confession, so if he had condemned her, then he would have acted in violation of the Law. Just a few verses later Jesus said that he judged no one (
John 8:15) and he also said that he came not to judge (
John 12:47), so he did not exercise authority as a magistrate and did not condemn her, but he did recognize her action as sin, and told her to go and sin no more.
In Isaiah 45:25, it says that all Israel will be saved, so many Jews mistakenly thought that meant that Gentiles had to become Jewish proselytes in order to become saved, which meant becoming circumcised and joining the group of people who agreed at Sinai to do everything Moses said (Exodus 20:19, Deuteronomy 5:22-33). Moses had the authority to make interpretations of Law and by the 1st century those who had this authority passed down to them were referred to as sitting in Moses' seat and it had become a large body of Jewish or laws, traditions, rulings, and fences that Jesus referred to as placing a heavy burden on the people (Matthew 23:2-4). So by becoming circumcised Gentiles were agreeing to become Jewish proselytes and to live as Jews according to all of their oral laws and doing that all in order to become saved, and this is what the Jerusalem Council rejected in Acts 15. While God did required all Jews to become circumcised, not even they were required to become circumcised for the purpose of becoming saved, and if God did not require it for that purpose, then it is therefore a man-made requirement, so the Jerusalem Council correctly upheld God's Law by rejecting this man-made requirement. Their discussion had absolutely nothing to do with whether or not Gentiles should follow the commands of their God. In Acts 15:21, it was expected that Gentiles would continue to learn how to obey the Law of Moses from hearing it taught every Sabbath in the synagogues.
In Acts 15:10, they were simply expressing the same opinion of Jewish oral laws that Jesus had expressed. In Deuteronomy 30:11-14, God said that what He commanded was not too difficult, in Romans 10:5-10, our faith should agree, and in 1 John 5:3, it confirms that the commands of God are not burdensome, so to interpret Acts 15:10 as referring to the Mosaic Law rather that Jewish oral laws is to put them in direct disagreement with God. Furthermore, to say that the Law is a heavy burden that no one could bear is to reflect a rather negative view on the giver of the Law. God said that what He commanded was for our own good and to prosper us (Deuteronomy 6:24, Deuteronomy 10:13) and the Psalms are full of extremely high praise for God's Law, especially Psalms 119. David said that he mediated on God's Law day and night, that those who obey it will be blessed, that God's Law is perfect, that he wanted God to show his grace to Him by teaching him to obey His Law, that he delighted in obey it, etc, and Paul also said he delighted in obeying God's Law (Romans 7:22), so he was on the same page as David, and the way that the average Jew viewed God's Law is completely incompatible with saying that it was a heavy burden no one could bear.