There are two sorts of truth we find in our Shastras, one
that is based upon the eternal nature of man — the one that deals with the eternal relation of God, soul, and
nature; the other, with local circumstances, environments of the time, social
institutions of the period, and so forth. The first class of truths is chiefly
embodied in our Vedas, our scriptures; the second in the Smritis, the Puranas,
etc.
We must remember that for all periods the Vedas are the
final goal and authority, and if the Puranas differ in any respect from the
Vedas, that part of the Puranas is to be rejected without mercy. We find, then, that in all these Smritis the teachings are
different. One Smriti says, this is the custom, and this should be the practice
of this age. Another one says, this is the practice of this age, and so forth.
This is the Achara which should be the custom of the Satya Yuga, and this is
the Achara which should be the custom of the Kali Yuga, and so forth.
Now this is one of the most glorious doctrines that you have, that eternal truths, being based upon the nature of man, will never change so long as man lives; they are for all times, omnipresent, universal virtues.
But the Smritis speak
generally of local circumstances, of duties arising from different environments,
and they change in the course of time. This you have always to remember that
because a little social custom is going to be changed you are not going to lose
your religion, not at all. . .
Swami Vivekananda