The Westminster Shorter Catechism
Q73. Which is the Eighth Commandment?
A. The Eighth Commandment is, Thou shalt not steal.[1]
[1] Exodus 20:15.
The Eighth Commandment is another of those commandments that is commonly known to be in the Decalogue, even by unbelievers. Indeed, even those who have never heard about Christ or Christianity is likely also to know that it is wrong to steal. This is because the works of the moral law is written in the hearts of man created in the image of God (Rom 2:1415): which is why man has a sense of morality whereas animals do not.
However, because of the corruption of nature, most people think of stealing
only as referring to illegally possessing of money or property that belong to
others. Like the other commandments, however, the Eighth Commandment has a
greater scope than that. For example, habitual late-coming is a breaking of the
Eighth Commandment, because it involves stealing the time of others. Similarly,
when a person breaks the Sabbath by doing unnecessary work, he is actually
stealing from God, because one day in seven belongs to the Lord and the only
kinds of work permitted are those that God allows in His Word.
Nevertheless, it is true that the Eighth Commandment has a primary reference to
private ownership, or the wealth and outward estate of ourselves and of others.
This compares with the Fifth Commandment which has to do with human
authorities; the Sixth Commandment which has to do with human life, the Seventh
Commandment which has to do with the moral purity of man, the Ninth Commandment
which has to do with the promotion of truth between man and man, and the Tenth
Commandment which has to do with the heart and desires of man.
Thus, it is most helpful to teach children to observe the Eighth Commandment by
getting them to honour the right of ownership of others. For example, children
should be taught from young that they must not take other childrens toys
without permission from the owners. In the same way, when a child picks up
something that has been accidentally misplaced by another, he should be taught
to return it if the owner can be found.