d by custom, were sanctioned by fear and reverence for the
law."

Reply Obj. 1: The human reason cannot have a full participation of
the dictate of the Divine Reason, but according to its own mode, and
imperfectly. Consequently, as on the part of the speculative reason,
by a natural participation of Divine Wisdom, there is in us the
knowledge of certain general principles, but not proper knowledge of
each single truth, such as that contained in the Divine Wisdom; so
too, on the part of the practical reason, man has a natural
participation of the eternal law, according to certain general
principles, but not as regards the particular determinations of
individual cases, which are, however, contained in the eternal law.
Hence the need for human reason to proceed further to sanction them
by law.

Reply Obj. 2: Human reason is not, of itself, the rule of things: but
the principles impressed on it by nature, are general rules and
measures of all things relating to human conduct, whereof the natural
reason is the rule and measure, although it is not the measure of
things that are from nature.

Reply Obj. 3: The practical reason is concerned with practical
matters, which are singular and contingent: but not with necessary
things, with which the speculative reason is concerned. Wherefore
human laws cannot have that inerrancy that belongs to the
demonstrated conclusions of sciences. Nor is it necessary for every
measure to be altogether unerring and certain, but according as it
is possible in its own particular genus.
________________________

FOURTH ARTICLE [I-II, Q. 91, Art. 4]

Whether There Was Any Need for a Divine Law?

Objection 1: It would seem that there was no need for a Divine law.
Because, as stated above (A. 2), the natural law is a participation
in us of the eternal law. But the eternal law is a Divine law, as
stated above (A. 1). Therefore there was no need for a Divine law in
addition to the natural law, and human laws derived therefrom.

Obj. 2: Further, it is written (Ecclus. 15:14) that "God left man in
the hand of his own counsel." Now counsel is an act of reason, as
stated above (Q. 14, A. 1). Therefore man was left to the direction
of his reason. But a dictate of human reason is a human law as stated
above (A. 3). Therefore there is no need for man to be governed also
by a Divine law.

Obj. 3: Further, human nature is more self-sufficing than irrational
creatures. But irrational creatures have no