On the other side of darkness

It's a new stage in getting through grief;
To see through saint alike and creeping thief.
To see through the lies; is to know the truth,
and it's limits in this black box of a material world,
where darkness is just on the other side of the light,
And our fear of the darkness is the real source of our fright.

I'm almost ready to move on,
but I don't know if I'll ever bravely whistle the songs,
I once whistled in my ignorance.