Well, the soul (or call it life) has left the body before burial so it doesn't go in the grave.
People have come back after being dead for some minutes, so it isn't an irreversible separation.
The best answer I've ever heard is in the following poem:
The sky may be clouded, yet ever the sun,
will sweep on it's way 'till the cycle is run,
and when into darkness the system is hurled,
again shall the builder reshape a new world.
Your path may be doubtful, uncertain your goal
- move on for your orbit is fixed to your soul:
and though it may lead into darkness of night,
the torch of the builder shall give you new light.
You were, you will be, know this while you are,
your spirit has travelled both long and afar,
it came from the scource, to the scource it returns,
the spark which was lighted eternally burns,
it took on strange garbs for long aeons of years,
and now in the soul of yourself it appears.
From body to body your spirit moves on,
it finds a new form when the old one has gone,
and the form that it finds is the fabric you wrought
on the loom of the mind from the fibre of thought.
As dew is drawn upwards in rain to descend,
your thoughts drift away and in destiny blend,
you cannot escape them, for petty or great,
or evil or noble, they fashion your fate.
Somewhere on some planet,sometime and somehow,
your life will reflect on your thoughts of your now
This Law is unerring, your fate is your own,
the structure you built you will live in alone.
You are your own devil, you are your own god,
you fashioned the paths that your footsteps have trod
and no-one can save you from error or sin
until you have hark'd to the spirit within.
Once list' to that voice and all tumult is done,
your soul's then in tune with the Infinite One.