Some people try to save God from this charge of partiality and
injustice by saying that all good things of this universe are the work
of God, and all evil things are the work of a demon or Satan. God
created everything good, but it was Satan who brought evil into this
world and made everything bad. Now let us see how far such a statement
is logically correct. Good and evil are two relative terms; the
existence of one depends upon that of the other. Good cannot exist
without evil, and evil cannot exist without being related to
good. When God created what we call good, He must have created evil at
the same time, otherwise He could not create good alone. If the
creator of evil, call him by whatever name you like, had brought evil
into this world, he must have created it simultaneously with God;
otherwise it would have been impossible for God to create good, which
can exist only as related to evil. As such they will have to admit
that the Creators of good and evil sat together at the same time to
create this world, which is a mixture of good and evil. Consequently,
both of them are equally powerful, and limited by each other.
Therefore neither of them is infinite in powers or omnipotent. So we
cannot say that the Almighty God of the universe created good alone
and not the evil.

Another argument which the Vedantists advance in support of the theory
of Reincarnation is that "Nothing is destroyed in the universe."
Destruction in the sense of the annihilation of a thing is unknown to
the Vedantic philosophers, just as it is unknown to the modern
scientists. They say "non-existence can never become existence and
existence can never become non-existence;" or, in other words, that
which did not exist can never exist, and conversely that which exists
in any form can never become non-existent. This is the law of