e it is fitting that some precepts should be given
about hope.

_I answer that,_ Among the precepts contained in Holy Writ, some
belong to the substance of the Law, others are preambles to the Law.
The preambles to the Law are those without which no law is possible:
such are the precepts relating to the act of faith and the act of
hope, because the act of faith inclines man's mind so that he
believes the Author of the Law to be One to Whom he owes submission,
while, by the hope of a reward, he is induced to observe the
precepts. The precepts that belong to the substance of the Law are
those which relate to right conduct and are imposed on man already
subject and ready to obey: wherefore when the Law was given these
precepts were set forth from the very outset under the form of a
command.

Yet the precepts of hope and faith were not to be given under the
form of a command, since, unless man already believed and hoped, it
would be useless to give him the Law: but, just as the precept of
faith had to be given under the form of an announcement or reminder,
as stated above (Q. 16, A. 1), so too, the precept of hope, in the
first promulgation of the Law, had to be given under the form of a
promise. For he who promises rewards to them that obey him, by that
very fact, urges them to hope: hence all the promises contained in
the Law are incitements to hope.

Since, however, when once the Law has been given, it is for a wise
man to induce men not only to observe the precepts, but also, and
much more, to safeguard the foundation of the Law, therefore, after
the first promulgation of the Law, Holy Writ holds out to man many
inducements to hope, even by way of warning or command, and not
merely by way of promise, as in the Law; for instance, in the Ps.
61:9: "Hope [Douay: 'Trust'] in Him all ye congregation of the
people," and in many other passages of the Scriptures.

Reply Obj. 1: Nature inclines us to hope for the good which is
proportionate to human nature; but for man to hope for a supernatural
good he had to be induced by the authority of the Divine law, partly
by promises, partly by admonitions and commands. Nevertheless there
was need for precepts of the Divine law to be given even for those
things to which natural reason inclines us, such as the acts of the
moral virtues, for sake of insuring a greater stability, especially
since the natural reason of man was clouded by the lusts of sin.

Reply Obj. 2: The precepts o