Is it maybe a different meaning of "abolish (katargeo)" or a different meaning of "law?" Because they seem somewhat contradictory.
Do we then make void [καταργοῦμεν] the law through faith? God forbid: yea, we establish the law. [Romans 3:31 KJV]
Having abolished [καταργήσας] in his flesh the enmity, even the law of commandments contained in ordinances; for to make in himself of twain one new man, so making peace; [Ephesians 2:15 KJV]
There is indeed more than one meaning of the word "law", and Romans ch3 v31 needs to be read in the light of v27;
"Boastfulness is excluded". But on what basis? By what law [NOMOS}? Is it by the law "of works" [ERGON]? No, it is by the law "of faith" [PISTEOS].
So when in v31 Paul says that their faith "upholds the law", he must be talking about "the law of faith", not the other one.
Whereas in Ephesians ch2 v15, and everywhere else where Paul talks against the law, he must be referring to "the law of works".
From these references, we may identify "the law of faith" as whatever law allows us in faith to set aside the detailed "law of works" provided by Moses.
First look at the meaning of καταργέω:
καταργέω ... ① to cause someth. to be unproductive, use up, exhaust, waste of a tree κ. τὴν γῆν Lk 13:7 (cp. ἀργεῖ οὐδὲν ἀλλὰ καρποφορεῖ OdeSol 11:23). ② to cause someth. to lose its power or effectiveness, invalidate, make powerless fig. extension of 1 ... τὰ ὄντα κ. nullify the things that (actually) exist 1 Cor 1:28. τὸν νόμον make the law invalid Eph 2:15; cp. Ro 3:31 ... ③ to cause someth. to come to an end or to be no longer in existence, abolish, wipe out, set aside τὶ someth. τὰ τοῦ νηπίου set aside childish ways 1 Cor 13:11.... ④ to cause the release of someone from an obligation (one has nothing more to do with it), be discharged, be released. -- Arndt, W., Danker, F. W., Bauer, W., & Gingrich, F. W. (2000). In A Greek-English lexicon of the New Testament and other early Christian literature (3rd ed., p. 525-526). University of Chicago Press.
While BDAG puts both verses with the meaning of (2), the context points to Eph. 2:15 having the meaning of (4), thus two different meanings for καταργέω.
The context is "he himself is our peace" in v14. We need to overcome what the English word for peace means to what שָׁלֵם means in the Old Testament law.
See Is the term שָׁלֹום (peace) in Isaiah 53:5 usually misunderstood? and Tetelestai - What did Jesus really say in John 19:30 assuming he spoke Aramaic or Hebrew?
Thus, Eph. 2:15 means Jesus Christ released us from the legal obligation of the Old Testament law by being the sacrifice for our sins. However, as in Rom. 3:31, he did not abolish the law but fulfilled it for us. In Romans 3 Paul wrote that sin is still valid (Rom. 3:23). In Eph. 2:15 Paul wrote that Jesus Christ paid the restitution for the Law.
The difference is between the context, not of semantic nuance of katargeo. In Romans, he is arguing that we do not nullify the law by faith, or the Christian faith doesn't nullify the law but fulfill it.
Ephesians verse is stating that Christ has lawfully according to God's plan, nullified the law, destroyed the dividing wall. Again, the implication is not that there's an enmity between Christian faith and law, since it has expired legally. We establish the law by following Christian faith.
First, what is the law being written about in Romans 3:31?
The whole chapter and its context must be grasped. Paul has been building up the case for God showing no partiality between Jews and Gentiles. God will judge the world impartially. On what basis? That everyone is under sin (vs. 9). Whatever the law says, it says to all who are under the law, and as both Jews and Gentiles alike stand condemned as law-breaking sinners, they will all be silenced before the Judge of all the Earth who will find them guilty. That is what the perfect law of God does. Nobody can keep it; everyone breaks it, therefore the law condemns everyone as unrighteous - 1 Timothy 1:9. And, as Paul says a few verses before the verse in question:
"Therefore by the deeds of the law there shall no flesh be justified in his sight: for by the law is the knowledge of sin. But now the righteousness of God without the law is manifested, being witnessed by the law and the prophets; even the righteousness of God by faith of Jesus Christ unto all and upon all them that believe. For there is no difference, for all have sinned and come short of the glory of God." Romans 3:20-23 K.J.
That makes clear, then, that believers who have faith in Christ do not make void the perfect law of God. Faith actually establishes it - as what? As being one of the two witnesses that establihes the righteousness of God by faith of Jesus Christ to all who believe. The second witness is the prophets.
Second, what is the law being written about in Ephesians 2:15?
It is clearly stated to be "the law of commandments, contained in ordinances". So, what does that verse say about that? Why, that it has been abolished in Christ's flesh. But it says a bit more that must not be missed out! What Christ achieved in his flesh resulted in the enmity against God by Jews and Gentiles being abolished (that enmity being the law that none of them could keep). Now peace could join believing Jews and Gentiles together, finally reconciled to God through what Christ achieved by the cross. The enmity was gone. Christ took it away by the perfect sacrifice of himself.
That is how "the righteousness of God without the law is manifested", "even the righteousness of God by faith of Jesus Christ unto all and upon all them that believe." That's the Romans 3:20-23 bit again.
It has now be shown what the "reconciliation" is that Paul refers to.
There is no need to wonder if the problem has been a different meaning of "abolish (katargeo)" or a different meaning of "law (nomos)." No. There is nothing wrong with the use of those words. Because reconciliation has been achieved, the law has served its purpose - Christ has fulfilled it so that it has, indeed, served to lead to the reality - Christ. It was only ever the shadow. Believers have stepped away from the shadow to live holy lives in faith of Christ, reconciled to God. They are at peace; new creatures in Christ - Colossians 2:10-17.
Making the law void is one thing, and annulling it is quite another. Christ was the fulfillment of the law. He never made it void. But a marriage is annulled when one party dies, and then the will (testament) of the deceased comes into effect. Jesus died in the flesh, thereafter the new testament in his blood came into effect. Release from the condemnation of the law, and inheriting the new covenant in his blood took place. Hebrews 8:13 to 9:1-17 gives all the details for that, showing what the reconciliation is all about.
Ephesians is about the law 'contained in ordinances'
'...ordinances, (touch not; taste not; handle not...' Colossians 2:20-21
One can eat pork, adorn mixed fabric, and other such things, after Christ, one no longer needs be concerned about all the ordinances in the law.
Romans is about the law in general. 'Love works no ill to his neighbor, therefore love is the fulfilling of the law' Romans 13:10
