Transmigration

The soul takes with it subtle parts of the gross elements as the seed.

It descending from heaven have a residual actions, which determines their birth.

                      What is exhausted in heaven is only that action which gave the soul a birth as god in heaven, but on the exhaustion of this action the residual action, good and bad, brings it back to earth. Otherwise it is difficult to explain the happiness or misery of  newborn child. Neither is it possible that in one life the entire  action of the previous life is worked out. For a man might have done both good work like sacrifices, as a result of which he is born as a god, and bad work, which can be worked out in animal body; and the working out of both kinds of actions simultaneously in one birth is impossible. So though by the enjoyment of heaven the result of good work like sacrifices etc. is exhausted, there are other actions in store according to which a man is born again in good or bad environment."Those whose conduct has been good will quickly attain some good birth." Action they are born in a noteworthy place,and situations, with becoming appearance, longevity, knowledge, wealth, happiness, intellect." so the soul is born with residual action. By what way does it descend?
Having dwelt there tll work is consumed,they return again the way they went by., which means that all their action is exhausted and there is nothing left. Moreover, it is reasonable to think that action done in one life (as human) is worked out in the next as god,
  No, what is exhausted in heaven is only that action which gave the soul a birth as god in heaven, but on the exhaustion of this action the remaining action, good and bad, brings it back to earth.

  

  " Otherwise it is difficult to explain the happiness or misery of a newborn child."

"Neither is it possible that in one life the entire action of the previous life is worked out."

" For a man might have done both good work like sacrifices, as a result of which he is born as a god, and bad work, which can be worked out in an animal body ; and the working out of both kind of Action simultaneously in one birth is impossible."

"So though by the enjoyment of heaven the result of good work lke sacrifices etc. is exhausted, there are other Action in store according to which a man is born again in good or bad environments."

-------BRAHMA SUTRAS