What is the aim of the soul to come on this earth?

As far as I can see it.... according to some Hindu concepts, God is like an ocean of purity, to be as simple and meaningful as possible, the soul is like a drop of impure water of that ocean.......and its purpose on earth is to attain purification slowly and steadily... through the process of births and rebirths..... and finally be pure enough to find this cycle of births and rebirths useless to it.. and that's when its purified enough to mix and lose itself forever in that ocean of purity.... called God.This is otherwise called attainment of salvation.