As to piety towards the gods you must know that this is the chief
thing, to have right opinions about them, to think that they exist, and
that they administer the All well and justly; and you must fix yourself
in this principle (duty), to obey them, and to yield to them in
everything which happens, and voluntarily to follow it as being
accomplished by the wisest intelligence. For if you do so, you will
never either blame the gods, nor will you accuse them of neglecting
you. And it is not possible for this to be done in any other way than
by withdrawing from the things which are not in our power, and by
placing the good and the evil only in those things which are in our
power. For if you think that any of the things which are not in our
power is good or bad, it is absolutely necessary that, when you do not
obtain what you wish, and when you fall into those things which you do
not wish, you will find fault and hate those who are the cause of them;
for every animal is formed by nature to this, to fly from and to turn
from the things which appear harmful and the things which are the cause
of the harm, but to follow and admire the things which are useful and
the causes of the useful. It is impossible then for a person who thinks
that he is harmed to be delighted with that which he thinks to be the
cause of the harm, as it is also impossible to be pleased with the harm
itself. For this reason also a father is reviled by his son, when he
gives no part to his son of the things which are considered to be good;
and it was this which made Polynices and Eteocles enemies, the opinion
that royal power was a good. It is for this reason that the cultivator
of the earth reviles the gods, for this reason the sailor does, and the
merchant, and for this reason those who lose their wives and their
children. For where the useful (your interest) is, there also piety is.
Consequently he who takes care to desire as he ought and to avoid
([Greek: echchlinein]) as he ought, at the same time also cares after
piety. But to make libations and to sacrifice and to offer first-fruits
according to the custom of our fathers, purely and not meanly nor
carelessly nor scantily nor above our ability, is a thing which belongs
to all to do.