The Natural Law
The natural law, known by reason, is the universal moral law of human nature for living well.
It is ‘natural’ because it is founded on what is good for human nature and because we can know it by our natural faculty of reason.
The natural law is valid for all people in all societies. Its principles can be understood by reason, even without faith. For example, dishonouring parents, murder, theft, adultery and lying are recognised by practically all human societies as being contrary to what is good for human life.
Christians have a duty to uphold the precepts of the natural law, both because these are rational and good in themselves and because they are part of God’s will for us, ‘written’ into our shared human nature.
Natural and civil law
Civil laws apply the principles of natural law to determine what is good for particular societies. For example, the natural law forbids murder. Many more detailed civil laws are required, however, to extend this principle to defining, for instance, good medical practice and legitimate action in war.
Christians have a duty to promote good legislation and to obey the civil laws of the societies they live in.
Nevertheless, particular civil laws can sometimes violate natural law, examples being the racial laws of Nazi Germany or laws permitting the killing of the unborn. Legitimate civil laws can never oblige anyone to commit sin.
The Ten Commandments
The Ten Commandments are the ten universal laws given directly by God to Moses on Mount Sinai.
They contain God’s specific codification of the main principles of the natural law. God revealed these commandments because Original Sin made it hard for human beings to discern good from evil. Jesus confirmed the necessity of the Ten Commandments:
Someone came to him and said, “Teacher, what good deed must I do to have eternal life?” And he said to him… “If you wish to enter into life, keep the commandments.” Matthew 19:16-17
The natural law and the law of grace
As well as the Ten Commandments, Christians also follow the new ‘law of grace’. The essence of the law of grace is to follow Jesus Christ in his Church, putting our possessions and lives at the service of God and others in charity. The law of grace guides us to heaven.
“If you wish to be perfect, go, sell your possessions, and give the money to the poor, and you will have treasure in heaven; then come, follow me.” Matthew 19:21
The Ten Commandments (or Decalogue)
1 I am the Lord your God, you shall not have strange gods before me.
God, as our creator, wants us to love him above all else.
2 You shall not take the name of the Lord your God in vain.
God’s name and all things dedicated to him should not be misused or treated lightly.
3 Remember to keep holy the Lord’s day.
God wants us to dedicate specific periods of time to him since worship is of the greatest importance.
4 Honour your father and your mother.
The family is the basis of society. Respect and obedience is due to parents and other lawful authorities.
5 You shall not kill.
To destroy or harm human life, made in God’s image, is a rejection of God’s gift, the person and society.
6 You shall not commit adultery.
Marriage is the only legitimate context for sexual acts. Adultery violates this sacred bond and destabilises families.
7 You shall not steal.
Personal property is needed for human well-being. Stealing is an attack on personal and civic life.
8 You shall not bear false witness against your neighbour.
To lie or attack a person’s reputation is an attack on human dignity. It is an injustice in itself and leads to further wrongs.
9 You shall not covet your neighbour’s wife.
To desire what is evil is itself evil. Impure thoughts corrupt our minds and can lead to immoral actions.
10 You shall not covet your neighbour’s goods.
God wants us to make full use of the gifts he has given us, not to crave possession of the gifts of others instead.