Not sure what you are saying. If you are saying that the Greek word "dogma" appears in Eph 2:15, please cite your sources.
G1378 - dogma - Strong's Greek Lexicon (kjv)
The Bible refers to multiple categories of law of the than the Law of God, such as the law of sin and works of the law. For example, in Romans 3:27, Paul contrasted a law of works with the law of faith, and in Romans 7:25-8:2, he contrasted the Law of God with the law of sin and contrasted the Law of the Spirit of life with the law of sin and death, so justification always needs to be given for why a particular verse should be interpreted as referring to the Law of God, especially when using a Greek word that is not what is normally used to refer to the Law of God, when every other time that word is used by the Bible refers to something other than the Law of God.
Not sure what any of this has to do with the question of whether the law of Moses still applies. Yes, for the
Jew,
Romans 3:20 declares that the Law brings knowledge of sin. But that certainly does not mean that the Law is permanent. Perhaps something will come along in God's evolving redemptive plan that will supplant the Law of Moses in terms of giving knowledge of sin.
As for
1 John 3:4, there is no specific reference to Torah here, just lawlessness
generally. To say that sin is lawlessness does not force us to conclude that a
particular law - in this case the Law of Moses - remains in force.
In Matthew 4:15-23, it says that it is a light for Gentiles, so His Gospel message is not just for Jews, but rather he prophesied that it would be proclaimed to all nations (Matthew 24:12-14) and commissioned to his disciples with it to make disciples of all nations (Matthew 28:16-20). It was the same Gospel that Peter taught (Acts 2:38) and that Paul taught (Romans 15:18-19). In John 4:22, Jesus said that salvation is of the Jews, so our understanding of salvation from sin should be with respect to what Jews know to be sin.
The actions that are and are not sin are based on God's eternal nature, which has been expressed through His law, which is why the Bible often uses the same terms to describe the nature of God as it does to describe the nature of God's law, such as with it being holy, righteous, and good (Romans 7:12). If the way to act in accordance or against God's righteousness were to evolve over time, then God's righteousness would not be eternal, but it is eternal (Psalms 119:142), therefore any laws that God has ever given for how to act in accordance with his righteousness are also eternal (Psalms 119:160).
Likewise, sin was in the world before God's law was given (Romans 5:13), so there were no actions that became righteous or sinful when the law was given, but rather the law revealed what has always been and will always be the way to do that. For example, in was sinful to commit adultery in Genesis 39:9 long before the Mosaic Covenant was made, during it, and after it has become obsolete, and if that were to ever change, then God's eternal righteousness would not be eternal. God can certainly give progressive revelation, but everything that He reveals at a later time will always be in accordance with what He has previously revealed and it will never become righteous to commit adultery no matter how many covenants God makes. The Torah is how the Israelites knew what sin is (Romans 3:20), so it shouldn't be a mystery that 1 John 3:4 is referring to the Torah, especially when the Torah is God's instructions for how to know Him (Exodus 33:13, 1 Kings 2:1-3), and in 1 John 3:4-6, those who continue to practice sin have neither seen nor known him.
Here is
1 Peter 2:21-22
For you have been called for this purpose, because Christ also suffered for you, leaving you an example, so that you would follow in His steps, 22
He who committed no sin, nor was any deceit found in His mouth;
Where does it say Jesus perfectly obeyed the Law of Moses? It says he committed no sin - this is not quite the same thing. We can discuss the subtleties of this distinction but, either way, we know that Jesus did not perfectly obey the Law of Moses! He challenged the food laws, declaring that nothing that goes into a man defiles him and he also challenged the law about stoning adulterers. And he "tested" / challenged the Law of Moses many other times.
Not least in suggesting that He (Jesus) was the place to go for forgiveness when the Law of Moses clearly prescribed that it was the
Temple that served this role.
In Galatians 4:4, Jesus was born under the Law of Moses, so he was obligated to obey it, and he was sinless, so he never broke it, which includes Deuteronomy 4:2, which forbids adding to or subtracting from the Law of Moses. Jesus was a Jew, so even if it were grants that the Law of Moses only defined what sin is for Jews, him being sinless would mean that he perfectly obeyed the Law of Moses.
Jesus was one with the Father, so he should not be interpreted as being in disagreement with what the Father has commanded, so he never challenged food laws or anything else the Father commanded. In John 6:39, Jesus came only to do the Father's will, in John 14:24, he said that his teachings were not his own, but that of the Father. In Deuteronomy 13:4-5, the way that God instructed His people to determine that someone is a false prophet who was not speaking for Him was if they taught against obeying His law, so if Jesus had done as you suggest, then according to God we should regard him as being a false prophet.
In Matthew 15:2-3, Jesus was asked why his disciples weren't following the tradition of the elders and he responded by asking them why they broke the command of God for the sake of their tradition, in Matthew 15:6, he said that for the sake of their tradition they made void the word of God, in Matthew 15:8-9, he said that they worshiped God in vain because they were teaching as doctrine the commandments of men, in Mark 7:6-9, he criticized them as being hypocrites for setting aside the commands of God in order to establish their own tradition, and in Matthew 15:20, he was still speaking against the tradition spoken about in Mark 7:3-4 of being made common by eating with unwashed hands. So Jesus was making a stark distinction between the commandments of God and the traditions of men and he should be interpreted as speaking against the traditions of men rather than as even more hypocritically turning around and doing what he just finished criticizing them as being hypocrites for doing.
John 8:1-12 is an example of Jesus acting in accordance with the Mosaic Law requires. 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 19:15), and he did not have a confession, so if he had condemned her, then he would have acted in violation of the Mosaic 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.
