According to the Lord Jesus Christ himself, the greatest commandments in the law are these two: “Thou shalt love the Lord thy God with all thy heart, and with all thy soul, and with all thy mind. This is the first and great commandment. And the second is like unto it, Thou shalt love thy neighbour as thyself” (Matthew 22:37-39).
Should we not obey these great commandments? Not in order to become Christians—but as Christians? Yes, of course we should. And it should be our pleasure to do so.
Remember also, that in the Sermon on the Mount1 our Lord expounded the spiritual depths of the moral law, clearly referring back to the Ten Commandments. Christ concludes his sermon with the following analogy, to teach us the importance of obedience: “Therefore whosoever2 heareth these sayings of mine, and doeth them, I will liken him unto a wise man, which built his house upon a rock: And the rain descended, and the floods came, and the winds blew, and beat upon that house; and it fell not: for it was founded upon a rock. And every one that heareth these sayings of mine, and doeth them not, shall be likened unto a foolish man, which built his house upon the sand: And the rain descended, and the floods came, and the winds blew, and beat upon that house; and it fell: and great was the fall of it” (Matthew 8:24-27).
We believe that as Christians—people who are saved by the Saviour—we should live moral lives. This includes loving our neighbour (as per Christ’s second greatest commandment)—and this surely includes loving fellow Christians. Christ directly says, “A new commandment I give unto you, That ye love one another; as I have loved you, that ye also love one another. By this shall all men know that ye are my disciples, if ye have love one to another” (John 13:34-35).
This is, clearly, the very same “law of Christ” that the apostle Paul refers to in his epistle to the Galatians where he instructs us, “Bear ye one another’s burdens, and so fulfil the law of Christ”3. (Galatians 6:2). For one obvious way in which we demonstrate our love for one another is in mutual support within the Christian church.
This “law of Christ” is not a subsitute or alternative moral standard that Christians should keep instead of God’s moral law (as summarised in the Ten Commandments). Neither is it a more concise summary that we should adopt in place of Christ’s two greatest commandments.
The apostle John teaches Christians: “Beloved, if our heart condemn us not, then have we confidence toward God. And whatsoever we ask [in prayer to God], we receive of him, because we keep his commandments, and do those things that are pleasing in his sight. And this is his commandment, That we should believe on the name of his Son Jesus Christ4, and love one another, as he gave us commandment. And he that keepeth his commandments dwelleth in him, and he in him. And hereby we know that he abideth in us, by the Spirit which he hath given us” (1 John 3:21-24).
Did you see what John did, there?
Knowing full well what Christ had declared to be the two great commandments in the law, the apostle insightfully expounds the first (“Thou shalt love the Lord thy God with all thy heart, and with all thy soul, and with all thy mind”) as requiring this: “that we should believe on the name of his [God’s] Son Jesus Christ”. He then cites the second: “and love one another, as he gave us commandment” (referring also to Christ’s repeated command to do the same; see John 13:34-35; 15:12, 17).
So, according to the apostle John, we Christians should keep God’s commandments, which are summed up in the two greatest commandments—and the ultimate way in which we keep the first and greatest commandment is by our believing on (or, in) the name of his Son, Jesus Christ. For if you love God, you will love his only begotten Son. “And there came a voice out of the cloud, saying, This is my beloved Son: hear him” (Luke 9:35; see also John 1:14, 18; 5:19-23; 14:1, 9-10).
So then, we should keep God’s commandments and we should keep his commandment5 to believe in his Son Jesus Christ.
The commandment to believe in Christ does not replace the commandments of the moral law in the way we should live, as Christians.
Our being Christians does not exempt us from keeping God’s moral law.
Our believing in Christ doesn’t mean that we are somehow automatically keeping all the moral law.
The “law of Christ” to lovingly bear the burdens of fellow Christians does not replace the moral law for Christians.
The “law of Christ” involves obedience to the moral law’s second greatest commandment.
That Christians must keep the two greatest commandments in the moral law is no argument against keeping all the moral law.
Christians should still be interested in keeping God’s commandments, and doing those things that are pleasing in his sight.
The apostle would have us understand that real communion with God in prayer is closely related to doing what is pleasing in God’s sight; namely, keeping his commandments (1 John 3:21).
John is correct about this, of course. Surely, living according to God’s moral standards is something we really ought to do. God’s command to believe the Gospel does not revoke or supercede that.
If you cannot remember it, then learn Matthew chapters 6-8. ↩︎
It will not do to argue that after Pentecost (Acts 2), or at the birth of the New Testament Church, all the Old Testament Laws—and Christ’s own teaching on them here—are done away with. No, but Christ’s “whosoever” here must include you. ↩︎
See also chapter 44, Add to Your Faith (4): Brotherly Kindness and Charity. ↩︎
The law of God should focus us on this one commandment of God: believe in the Lord Jesus Christ. Or as Paul says, the law is the schoolmaster to bring us to Christ. See chapter 26, The Schoolmaster to Bring Us Unto Christ. ↩︎
It was not only the apostle John who used a word usually associated with the Law when they teach us about the Gospel. While John referred to God’s call to believe in his Son as a commandment, Paul and Peter wrote of obeying the Gospel (Romans 10:16; 2 Thessalonians 1:8; 1 Peter 4:17) and obedience to the faith (Romans 1:5; 16:26). ↩︎