Swami Vivekananda has said in his various discussion of the Vedas that the spiritual laws mentioned in the Vedas are eternal.
There was a time when the Vedas themselves were considered eternal in
the sense in which the divine truths contained therein were changeless
and permanent and were only revealed to man. At a subsequent time, it
appears that the utterances of the Vedic hymns with the knowledge of
its meaning was important; and it was held that the hymns themselves
must have had a divine origin. At a still later period, the meaning of
the hymns showed that many of them could not be of divine origin,
because they inculcated upon mankind performance of various unholy
acts, such as torturing animals; and we can find many ridiculous
stories in the Vedas. The correct meaning of the statement "The Vedas
are beginningless and eternal" is that the law or truth revealed by
them to man is permanent and changeless. Logic, geometry, chemistry,
etc., reveal also a law or truth which is permanent and changeless and
in that sense they are also beginningless and eternal. But no truth or
law is absent from the Vedas, and I ask any one of you to point out to
me any truth which is not treated of in them.
(The Complete Works of Swami Vivekananda, Vol.5: With the Swami Vivekananda at Madura, pp.205-206)
The Hindus have received their religion through revelation, the Vedas.
They hold that the Vedas are without beginning and without end. It may
sound ludicrous to this audience [in the West] how a book can be
without beginning or end. But by the Vedas no books are meant. They
mean the accumulated treasury of spiritual laws discovered by
different persons in different times. Just as the law of gravitation
existed before its discovery and would exist if all humanity forgot
it, so is it with the laws that govern the spiritual world. The moral,
ethical, and spiritual relations between soul and soul and between
individual spirits and the Father of all spirits were there before
their discovery, and would remain even if we forget them.
(The Complete Works of Swami Vivekananda, Vol.1 Paper on Hinduism, pp.6-7.)
[Vedic] principles have existed throughout time; and they will exist.
They are non-created - uncreated by any laws which science teaches us
today. They remain covered and become discovered, but are existing
through all eternity in nature. If Newton had not been born the law of
gravitation would have remained all the same and would have worked all
the same. It was Newton's genius which formulated it, discovered it,
brought it into consciousness, made it a conscious thing to the human
race. So are these religious laws, the grand truths of spirituality.
They are working all the time. If all the Vedas and Bibles and Korans
did not exist at all, if seers and prophets had never been born, yet
these laws would exist. They are only held in abeyance, and slowly but
surely will work to raise the human race, to raise human nature. But
they are the prophets who see them, discover them; and such prophets
are discoverers in the field of spirituality. As Newton and Galileo
were prophets of physical science, so are they prophets of
spirituality. They can claim no exclusive right to any one of these
laws; they are the common property of all nature.
The Vedas, as the Hindus say, are eternal. We now understand what they
mean by their being eternal, i.e. that the laws have neither beginning
nor end. Earth after earth, system after system, will evolve, run for
a certain time, and then dissolve back into chaos; but the universe
remains the same. Millions and millions of systems are being born,
while millions are being destroyed. The universe remains the same. The
beginning and end of time can be told as regards a certain planet;
but, as regards the universe, time has no meaning at all. So are the
laws of nature, the physical laws, the mental laws, the spiritual
laws, without beginning or end; and it is within a few years,
comparatively speaking - a few thousand years at best - that man has
tried to reveal them. The infinite mass remains before us. Therefore
the one great lesson that we learn from the Vedas, at the start, is
that religion has just begun. The infinite ocean of spiritual truth
lies before us to be worked on, to be discovered, to be brought into
our lives. The world has seen thousands of prophets, and the world has
yet to see millions.
(The Complete Works of Swami Vivekananda, Vol.6: The Methods and Purpose of Religion, pp.8-9.)
The Vedas are anadi, eternal. The meaning of the statement is not, as
is erroneously supposed by some, that the words of the Vedas are
anadi, but that the spiritual laws inculcated by the Vedas are such.
These laws, which are immutable and eternal, have been discovered at
various times by great men or rishis, though some of them have been
forgotten now, while others are preserved.
(The Complete Works of Swami Vivekananda, Vol.6: Notes Taken Down in Madras, 1892-93, p.103)