To clarify my view of "moral law", I see two understandings by people. Some say the Ten Commandments are the moral law; but I insist they contain the moral law. The moral law in substance existed from creation forward, God's law, that does not change. In the Law of Moses, the moral law is given in a particular way that was applied to Israel. So when I insist the entire Law of Moses, the Old Covenant, was abolished, including the Ten Commandments; I do NOT mean the substance of moral law that has existed since creation and still exists in Christ's law today. I am not antinomian nor a dispensationalist.
God's nature is eternal, so all of God's laws for how to testify about God's nature are therefore also eternal (Psalms 119:160), so all of the Mosaic Law has existed from creation forward and does not change. In Deuteronomy 5:31-33, Moses wrote down everything that God commanded him without departing from it, so all of the Mosaic Law is God's eternal law. At no point does the Bible suggest that it can ever be moral to disobey God. Morality is in regard to what we ought to do and we ought to obey God, so all of God's laws are inherently moral laws. Christ taught obedience to the Mosaic Law both by word and by example, so it is the Law of Christ.
From Heinrich August Wilhelm Meyer, a 19th century German Lutheran Greek scholar:
"Ephesians 2:15. τὴν ἔχθραν] This, still included in dependence upon λύσας, is now the μεσότοιχον broken down by Christ: (namely) the enmity. It is, after the example of Theodoret (comp. τινές in Chrysostom),
understood by the majority (including Luther, Calvin, Bucer, Clarius, Grotius, Calovius, Morus, Rosenmüller, Flatt, Meier, Holzhausen, Baumgarten-Crusius, de Wette) of the Mosaic law as the cause of the enmity between Jew and Gentile, in which case the moral law is by some included, by others excluded. But, in accordance with Ephesians 2:14, the reader is led to nothing else than the opposite of εἰρήνη, i.e. to the abstract enmity; and in the sequel, indeed, the abolition of the law is very definitely distinguished from the destruction of the enmity (as means from end). Hence the only mode of taking it, in harmony with the word itself and with the context, is: the enmity which existed between Jews and Gentiles, comp. Ephesians 2:16."
Ephesians 2 - Heinrich Meyer's Critical and Exegetical Commentary on the New Testament - Bible Commentaries - StudyLight.org
I used to interpret Ephesians 2:15 as referring to the Mosaic Law, so I can certainly see why many people do that, but I think that it stems from a bias against the Mosaic Law that leads us to systematically interpret verses as being against the Mosaic Law. I decided to try reading the NT as though its authors were in complete agreement with the extremely positive view of the Mosaic Law that is expressed in the Psalms and found that it makes much more sense and has much more continuity. I recognize that this is also a form of bias, though I think it is far more reasonable to consider those who consider the Psalms to be Scripture to be in agreement with them than to impose a negative view of the Mosaic Law onto them onto them that is incompatible with the view that the Psalms are Scripture.
In any case, the fact remains that the Mosaic Law was given as a light and a blessing to nations (Isaiah 2:2-3, 49:6), not as a dividing wall of hostility. Instructions for how to testify about God's nature can't be abolished without abolishing Christ, who is the exact expression of God's nature (Hebrews 1:3). Those who reject the Mosaic Law are rejecting the nature of who God has revealed Christ to be.
From the Appendix to the First London Confession of Faith Revised Edition 1646
"IX. Though we that believe in Christ, be not under the law, but under grace, Rom.6:14; yet we know that we are not lawless, or left to live without a rule; "not without law to God, but under law to Christ," 1 Cor.9:21. The Gospel of Jesus Christ is a law, or commanding rule unto us; whereby, and in obedience whereunto, we are taught to live soberly, righteously, and godly in this present world, Titus 2:11,12; the directions of Christ in His evangelical word guiding us unto, and in this sober, righteous, and godly walking, 1 Tim.1:10,11."
In Romans 6:14, it describes the law that we are not under as being a law where sin had dominion over us, which does not describe the Mosaic Law, which is a law where holiness, righteousness, and goodness have dominion over us (Romans 7:12), but rather it is the law of sin where sin had dominion over us. In Romans 6:15, because under grace does not mean that we are permitted to sin, and sin is the transgression of God's law (1 John 3:4), so we are still under God's law. It is contradictory to say that you are not under God's law and also that you are not without law to God, but rather in 1 Corinthian 9:21, Paul used a parallel statement to equate the Mosaic Law with the Law of Christ. Christ taught obedience to the Mosaic Law both by word and by example, so it would make sense to think that that the Law of Christ was something that that the law that Christ taught, which was given to testify about him. Jesus began his ministry with the Gospel message to repent for the Kingdom of God is at hand and the Mosaic Law was how his audience knew what sin is. Likewise, the Mosaic Law is God's instructions for how the Israelites knew how to live soberly, righteous, and godly in this present world.
"X. Though
we be not now sent to the law as it was in the hand of Moses, to be commanded thereby, yet Christ in His Gospel teacheth and commandeth us to walk in the same way of righteousness and holiness that God by Moses did command the lsraelites to walk in, all the commandments of the Second Table being still delivered unto us by Christ, and all the commandments of the First Table also (as touching the life and spirit of them) in this epitome or brief sum, "Thou shalt love the Lord thy God with all thine heart, etc.," Matt.22:37,38,39,40; Rom.13:8,9,10."
An Appendix to a Confession of Faith, 1646 | The Reformed Reader
All of the laws that God has given are examples of how to love God and our neighbor, which is why Jesus said that those are the greatest two commandments and that all of the other commandments hang on them, so they are all connected. The sum is inclusive of all of its parts, so if someone's obedience to the greatest two commandments is not inclusive of God's other commandments, then they are not treating the greatest two as being the sum of the other commandments.