In our assertion that Christians should keep the moral law of God (as summarised in the Ten Commandments, and in what the Lord Jesus Christ esteems to be the two greatest commandments), we are not seeking to add Moses to Christ, or to combine Law and Gospel, or to re-introduce law-obedience as a means of salvation or as any kind of supplement to the total salvation that the Saviour has provided for people.
We are simply affirming that the moral law of God is still the standard by which Christians ought to live. In this we are in full agreement with the apostle Paul’s teaching on this matter in Galatians chapters 4 and 5.
In Galatians 4, Paul explained:
Christians are not under the law (mount Sinai, and Old Testament Jerusalem) as a covenant of works, which Paul describes as being under “the [covenant] from the mount Sinai, which gendereth to bondage, which is Agar”1 (v.24).
But Christians are “under grace” in the “Jerusalem which is above”. The heavenly city of the covenant of grace “is free, which is the mother of us all” (v.26; compare also Hebrews 11:10, 16; Revelation 21:2).
“For these are the two covenants” (v.24); and Christians are “not children of the bondwoman, but of the free” (v.31), affirms the apostle.
So, does our being “children of the free” in the covenant of grace mean that we should have nothing to do with the law of God? Paul’s answer is in what we have as chapter 5 of his epistle, and his answer is twofold: we have no need to the ceremonial laws; but we should still keep the moral laws:
We have no need to keep the ceremonial laws: “Stand fast therefore in the liberty wherewith Christ hath made us free, and be not entangled again with the yoke of bondage” (Galatians 5:1). By “yoke of bondage”, Paul means the ceremonial parts of the Law of Moses—i.e. we should not get circumcised, and become a “debtor to do the whole law” (vv.2-12). For to keep any part of the Mosaic law in order to be saved is to deny that Christ alone is sufficient. So, for Christians there is to be no circumcision, sacrifices, feasts, priests, or anything else that the Lord Jesus Christ has fulfilled for us.
We should still keep the moral laws: “For, brethren, ye have been called unto liberty; only use not liberty for an occasion to the flesh, but by love serve one another” (v.13). With this, Paul begins to explain that Christians should still obey the moral law: “For all the law is fulfilled in one word, even in this; Thou shalt love thy neighbour as thyself. But if ye bite and devour one another, take heed that ye be not consumed one of another” (Galatians 5:13-15).
We have been called to liberty. This liberty is not a licence to sin, but it is a liberty in which we should by love serve one another—a liberty in which we should still keep “all the law”, Paul teaches us (he means, all the moral law).
In his reference to the moral law, the apostle is focused upon our loving service of one other, that should characterise Christian fellowship. All that we do should be done in fulfilment of (i.e. in the keeping of) the commandment, “Thou shalt love thy neighbour as thyself”, says Paul.
We recognise this commandment as what Christ hiself identifies as the second “great commandment in the law” (Matthew 22:39). Moreover, we can take it as a given that Paul also agrees with Christ, who declared that God’s “first and great commandment” has to do with our love and service toward him: “Thou shalt love the Lord thy God with all thy heart, and with all thy soul, and with all thy mind” (Matthew 22:38-39). Therefore, surely, all that we do must be done in the fulfilment of this greatest commandment, too.
Christians, being “Children of the free” (Galatians 4:31), are free to serve God. This service involves keeping God’s moral law, not sinning.
As Paul explains it in another place, we are not to be sin’s slaves any more but willing slaves of God: “Know ye not, that to whom ye yield yourselves servants2 to obey, his servants ye are to whom ye obey; whether of sin unto death, or of obedience unto righteousness? But God be thanked, that ye [Christians] were the servants of sin, but ye have obeyed3 from the heart that form of doctrine which was delivered you. Being then made free [by God] from sin, ye became the servants of righteousness” (Romans 6:16-18).
There are plenty of resources out there to help you in your study of God’s moral law as a Christian—to understand what is involved in being a servant of righteousness. You could start with one of the many of the Reformed Catechisms that have a built-in exposition of the Ten Commandments4. Then there are numerous commentaries, sermon-series and other books, by Reformers and Puritans and others who hold to these same teachings today.
In all these scources, you will find that the purpose is never to learn in order to obey and save yourself that way, or to contribute toward your salvation at all. No, but their message is always that the Ten Commandments should be learnt and obeyed in order to live a moral life, as a faithful Christian, to the glory of God.
If you are not ready to put your mind and heart into serious study of the law of God and consequent God-pleasing efforts at holy living, then I recommend you also learn and sing Psalm 119. Even if it takes you a hundred and nineteen times—do whatever it takes until you get it!
The Psalmist acknowledged that a work of God was required within him in order to open his eyes that he might behold wondrous things out of God’s law; to put new spiritual life into him; to incline him toward God’s moral laws and to make him to walk in them; to enable his soul thus to live (Psalms 119:18, 25, 33-38, 154, 156, 175).
Christians should have the same heart as the Psalmist: “O how love I thy law! it is my meditation all the day” (Psalm 119:97).
Now, do not say that you should have nothing to do with Psalm 119 “because that is in the Old Testament”. These are, surely, among the words of Christ that we should let dwell in us richly in all wisdom (see Colossians 3:16).
Agar is the servant woman Hagar in the Hebrew; see Genesis 16:2-3; 21:9-13. ↩︎
The Greek word translated “servant” is δοῦλος (doulos): a bond-servant, i.e. a devoted and willing slave (Strong’s Concordance). Doulos-servants have so much appreciation and respect for their master or mistress, that they consider it a great honour and benefit to themselves to be bound to them, and so they are not interested in escaping or being set free. This is how fallen mankind is toward sin, Paul is saying (see also John 8:34). And this is how Christians should be toward Christ. ↩︎
To obey a form or system of doctrine involves believing in it. Paul here referred to the Christian form of doctrine that had been delivered (i.e. preached and taught) to the church at Rome. ↩︎
For example, look at the catechisms among the historic Reformed Documents on https://reformed.org/ and the catechisms of the Reformed Baptists at https://www.reformedreader.org/. ↩︎