What is the Source ? The source from where life has come. What is the source from where are soul comes ? As many people take birth a new soul comes into this world. But where do the souls come from? Do souls also reproduce just like humans? Or are souls only limited to a certain number.
The thought here is once anyone leaves this world goes back to the source. But if the karmic balance of that soul is unbalanced, it returns to our world of materiality. It is only when the karmic balance of the soul is balanced, it returns permanently to the source.
So at times you see young people leave the world, and we think that god is cruel, and it was wrong of the young one leave the world. But what we don't realize is, that soul had very little left to complete balance of their karmic balance. Hence they permanently return to the source. It is said when all karmic balances, are balanced, that is when this world shall end.
The source is the ultimate goal for any human, but we are so into our materiality of life, we forget about the balance, and keep coming back to the world from the source.