Ethics is the system of morality followed. The question ethics asks is, what is right or wrong, good or bad. Under the OT the summary ten commandments form the basis of ethics. They are basic, concrete rules. They forbid certain blatant sins. Mostly they are negative, with the exception of the fourth and fifth commandments, which are positively stated and either imply or promise a blessing, as does the negative second commandment. The first and tenth commandments are internal, which show that the fulfilment of the commandments is to come from within.

As Reformed Christians we are still used to thinking about ethics from these ten commandments. However, these rules are an integral part of the OT Law covenant which has been fulfilled in our Lord Jesus Christ and come to an end. Therefore, a question hangs over the continued use of the ten commandments in Reformed Ethics: Are we justified in using them as the base for NT ethics and if so, what function do they have?

One thing we can discount immediately. They are not the way of becoming justified or deserving life, for we, under the NT, do not live under law, but under grace through faith. However, they still occupy an important place as house rules.

If we go back before the law was given we notice that there was a clear knowledge of wrong and right among God's people. We find all kinds of sins condemned in Genesis already and we also find the command to live righteously. The moral laws God gave Israel were simply a codification of what was always required by God, based on how He created us and how He expected us to relate to Him and each other. In other words, one aspect of the law is that they are codified rules for life. They are wise rules because they show us how to live in God's world together with our neighbour and how we will be blessed cf. Deut 4:6-8.

They were also given to sinners to curb sin 1 Tim 1:8-10. They are a restraint, because they carried a penalty, a curse for those who disobeyed them. However, the Law underwent a change for those in Christ, for He paid the penalty for our sins. For those, who are in Christ by faith, there is no penalty anymore since it has been enforced already. A law without penalties is a toothless tiger cf. Rom 4:15; 5:13. However, that is only true for those in Christ. For those who are not in Christ the penalty remains.

Consequently, the Law has changed for those in Christ only by dropping the penalty. That means they still continue as a guide for us to know God's good will, what He approves and what He hates. The two tables of the ten commandments highlight the two laws which sum up all the Law, love God above all things and love your neighbour as yourself.

The ten commandments, however, do not bring this love fully to the light. Only when we contemplate the Lord Jesus Christ do we begin to understand God's love for us and how man ought to love God and each other. We have the positive expression of the law made visible to us in Christ. The ten commandments are then a rudimentary, negative, revelation of God's will in comparison to Christ and not the sufficient basis for NT ethics.

NT ethics must be suffused with the knowledge of God as revealed in the Lord Jesus Christ. The Lord Jesus Christ was the first of the perfect New Man and those in Him are born again through faith. He is sinless and those who are in Him are sinless in Him and ought to be sinless in their living. NT ethics not only works with a law without penalties, but it also works with a renewed people, a Christlike people, who look to the Law as fulfilled in Christ to see how they are to live before God and the world.

However, since that renewal, is not complete we continue in to share in the fallen nature of Adam, whose sin still needs to be restrained. However, the restraint of sin comes more from within than from without. The Law still condemns sin and our renewed nature responds to that condemnation by resisting sin, or by condemning our sin when we fall into it. Our renewed nature also fears to be cut off from Christ and our fallen nature fears the penalty. Together our love and our fears keep us on the paths of God.

Can we do away then with the Law of God or the ten commandments as the summary? No, for we are dull of understanding and we need things spelled out for us. Have the Reformed Churches erred in basing their ethics on the ten commandments? Not if we see them fulfilled in Christ. The ten commandments are a door into the full revelation of what is good and right as revealed in Jesus Christ our Lord. They do give entrance into the knowledge of evil as fully exposed by the Lord Jesus Christ. Our knowledge of good and evil would not be complete without the law, but that revela­tion needed completion for us to understand it fully, and that revelation only came in our Lord Jesus Christ, who was made our Wisdom, that is our Righteousness, Sanctification and Redemption. To Him be the glory forever.