Christians are not slaves to the Mosaic Law, we are sons of God because we belong to Christ. This is the blockbusting conclusion of Galatians. It means we are heirs of the amazing promise of blessing that God gave to Abraham all the way back at the start of the Bible. It means we are redeemed and adopted. God has sent His Holy Spirit into our hearts and He makes us want to cry out “Abba, father” - an amazing family closeness that surpasses anything this world has to offer. Christians are clothed with Christ, literally having His righteousness put on us like a coat, in the place of our own righteousness that was like living in filthy, squalid rags.
The obvious question many ask when hearing this is "what, then, do we do with the Mosaic Law? Ignore it? Teach it as normal for Christians today? Modify the way it is taught in some way?"
This was the big issue in Galatia. Gentile believers were being told by Judaisers that they had to be circumcised and obey the whole law of Moses to be proper Christians. The temptation today is to assume that the Law was given to produce moral, godly behaviour. Incredibly provocatively Paul says in Galatians (and Romans) that it was given to highlight and increase sin, thereby driving us to say not "I can do this, and so be good enough for God" but "I can never do this and can only cry to him for a saviour."How, then, Should We Teach The Old Testament? Especially passages that are clearly Law-based? Many Old Testament passages delight in God’s Law. Should we teach them as directly applicable to Christians? And can we teach law evangelistically to non-Christians, using it to highlight sin so that they will repent and ask for grace?
Lets be very clear, Are we then to ignore and not teach anything from the Old Testament? No! We teach the Old Testament in such a way that it points to its own fulfilment in Christ and his glory.
Lets be very clear,New Covenant believers are not under Old Covenant legislation and practices. The law was summed up, completed, fulfilled and utterly obeyed on our behalf by Christ. We are no longer under it, either for our justification or for our sanctification (Gal 3:1-5). People could never obey the condemning law but it pointed them to the redeemer, thereby accomplishing its goal. Does this lower the bar on holiness or mean that our behaviour no longer matters, as some are clearly worried it does? No - just read Romans 6 and 7 to see how Paul answered that question
Are we then to ignore and not teach anything from the Old Testament? No! We teach the Old Testament in such a way that it points to its own fulfilment in Christ and his glory.
It is very easy to approach Old Testament passages with the automatic assumption that anything that God said there about Israel now applies directly to the Christian Church, and that everything he said about Jews applies directly to Christians. These are false assumption for a very important reason: the New Testament equivalent of Old Testament Israel is not directly the Church, but the perfect Israel, Jesus Christ. The New Testament equivalent of an Old Testament believer is someone who lives in Christ and is filled with the Holy Spirit.
Therefore when we read or teach the Old Covenant we ask not what it tells us directly about us, but first what it tells us about Jesus. Subsequently we discover, through the lens of Christ, what it teaches about those who are in Christ. In the particular matter of the law we need to ask first how it applies to Christ (He has perfectly fulfilled it) and only then how it applies to us (we are now under the law of Christ - God’s grace - not the Old Testament Mosaic Law).
Romans 3:21 is a verse beloved of evangelicals. It says that a righteousness is now revealed from God apart from Law, but to which the Law and Prophets testify. Righteousness from God is not found in the Law. It is found “apart from law”. Paul says that the purpose of the Law was to be prophetic about Jesus, pointing to the better way that He has opened up and the better righteousness he brought. The purpose of the Law when the Old Testament is taught to Christians is to testify to the righteousness of God found in Jesus.
We teach how the Law was redolent and prophetic of the glories of Christ. We delight in the fact that one will come who obeys it for us. We feel, with the original hearers, the stunning force of God's holiness. We cry with them over our sin and our helplessness without God's redeemer. We teach there is a New Covenant, a final sacrifice, a new meeting place with God, a great high priest, a greater prophet than Moses and a different Law - ALL JESUS! - who resolves our condemnation by the Law, takes away our transgressions, washes us clean by the Holy Spirit and makes us New Creations.
Basically the New Testament way to teach the fulfillment of the Law is Romans 8 - there is now no condemnation for those who are in Christ, for the law of the Spirit of Life has set me free from the law of sin and death. Hallelujah!