Life in Christ
The natural law is nothing other than the light of under
standing placed in us by God; through it we know what we
must do and what we must avoid. God has given this light
or law at the creation.
The natural law, present in the heart of each man and
established by reason, is universal in its precepts and its authority
extends to all men. It expresses the dignity of the person and
determines the basis for his fundamental rights and duties:
For there is a true law: right reason. It is in conformity with
nature, is diffused among all men, and is immutable and
eternal; its orders summon to duty; its prohibitions turn
away from offense . . . . To replace it with a contrary law is
a sacrilege; failure to apply even one of its provisions is for
bidden; no one can abrogate it entirely.
Application of the natural law varies greatly; it can de
mand reflection that takes account of various conditions of life ac
cording to places, times, and circumstances. Nevertheless, in the
diversity of cultures, the natural law remains as a rule that binds
men among themselves and imposes on them, beyond the inevita
ble differences, common principles.
The natural law is
and permanent throughout
the variations of history;
it subsists under the flux of ideas and
customs and supports their progress. The rules that express it
remain substantially valid. Even when it is rejected in its very
principles, it cannot be destroyed or removed from the heart of
man. It always rises again in the life of individuals and societies:
Theft is surely punished by your law, O Lord, and by the law
that is written in the human heart, the law that iniquity itself
does not efface.
The natural law, the Creator’s very good work, provides
the solid foundation on which man can build the structure of moral
rules to guide his choices. It also provides the indispensable moral
foundation for building the human community. Finally, it provides
the necessary basis for the civil law with which it is connected,
whether by a reflection that draws conclusions from its principles,
or by additions of a positive and juridical nature.
8 St. Thomas Aquinas,
III, 22, 33.
11 St. Augustine,
2, 4, 9: PL 32, 678.