A man is worthy to possess a thing or a state when his possession of
it is in harmony with the summum bonum. We can now easily see that all
worthiness depends on moral conduct, since in the conception of the
summum bonum this constitutes the condition of the rest (which belongs
to one's state), namely, the participation of happiness. Now it
follows from this that morality should never be treated as a
doctrine of happiness, that is, an instruction how to become happy;
for it has to do simply with the rational condition (conditio sine qua
non) of happiness, not with the means of attaining it. But when
morality has been completely expounded (which merely imposes duties
instead of providing rules for selfish desires), then first, after the
moral desire to promote the summum bonum (to bring the kingdom of
God to us) has been awakened, a desire founded on a law, and which
could not previously arise in any selfish mind, and when for the
behoof of this desire the step to religion has been taken, then this
ethical doctrine may be also called a doctrine of happiness because
the hope of happiness first begins with religion only.
We can also see from this that, when we ask what is God's ultimate
end in creating the world, we must not name the happiness of the
rational beings in it, but the summum bonum, which adds a further
condition to that wish of such beings, namely, the condition of
being worthy of happiness, that is, the morality of these same
rational beings, a condition which alone contains the rule by which
only they can hope to share in the former at the hand of a wise
Author. For as wisdom, theoretically considered, signifies the
knowledge of the summum bonum and, practically, the accordance of
the will with the summum bonum, we cannot attribute to a supreme
independent wisdom an end based merely on goodness. For we cannot
conceive the action of this goodness (in respect of the happiness of
rational beings) as suitable to the highest original good, except
under the restrictive conditions of harmony with the holiness * of
his will. Therefore, those who placed the end of creation in the glory
of God (provided that this is not conceived anthropomorphically as a
desire to be praised) have perhaps hit upon the best expression. For
nothing glorifies God more than that which is the most estimable thing
in the world, respect for his command, the observance of the holy duty
that his law imposes on us, when there is added thereto his glorious
plan of crowning such a beautiful order of things with corresponding
happiness. If the latter (to speak humanly) makes Him worthy of
love, by the former He is an object of adoration. Even men can never
acquire respect by benevolence alone, though they may gain love, so
that the greatest beneficence only procures them honour when it is
regulated by worthiness.
{BOOK_2|CHAPTER_2 ^paragraph 55}