d (Jer. 10:2): "Be not
afraid of the signs of heaven, which the heathens fear." Therefore the
heavenly lights were not made to be signs.

Obj. 2: Further, sign is contradistinguished from cause. But the
lights are the cause of what takes place upon the earth. Therefore
they are not signs.

Obj. 3: Further, the distinction of seasons and days began from the
first day. Therefore the lights were not made "for seasons, and days,
and years," that is, in order to distinguish them.

Obj. 4: Further, nothing is made for the sake of that which is
inferior to itself, "since the end is better than the means" (Topic.
iii). But the lights are nobler than the earth. Therefore they were
not made "to enlighten it."

Obj. 5: Further, the new moon cannot be said "to rule the night." But
such it probably did when first made; for men begin to count from the
new moon. The moon, therefore, was not made "to rule the night."

_On the contrary,_ Suffices the authority of Scripture.

_I answer that,_ As we have said above (Q. 65, A. 2), a corporeal
creature can be considered as made either for the sake of its proper
act, or for other creatures, or for the whole universe, or for the
glory of God. Of these reasons only that which points out the
usefulness of these things to man, is touched upon by Moses, in order
to withdraw his people from idolatry. Hence it is written (Deut. 4:19):
"Lest perhaps lifting up thy eyes to heaven, thou see the sun and the
moon and all the stars of heaven, and being deceived by error thou
adore and serve them, which the Lord thy God created for the service
of all nations." Now, he explains this service at the beginning of
Genesis as threefold. First, the lights are of service to man, in
regard to sight, which directs him in his works, and is most useful
for perceiving objects. In reference to this he says: "Let them shine
in the firmament and give life to the earth." Secondly, as regards the
changes of the seasons, which prevent weariness, preserve health, and
provide for the necessities of food; all of which things could not be
secured if it were always summer or winter. In reference to this he
says: "Let them be for seasons, and for days, and years." Thirdly, as
regards the convenience of business and work, in so far as the lights
are set in the heavens to indicate fair or foul weather, as favorable
to various occupations. And in this respect he says: "Let them be for
signs."

Reply Obj. 1: The lights in th