Answer:
Both punishment and sweet reward, It will befall both fool and lord. It is a spiritual scoreboard, Your every deed it does record.
I open wide and tight I shut, Sharp am I and paper-cut fingers too, so do take care, I'm good and bad, so best beware.
Sometimes I am loud. And viewed with distaste. Poke out my 'eye', then I'm on the front of your face.
It is more feared than fear itself, And no one can escape it. It takes no sides and does not judge, it does not know to hold a grudge. It is the most clearest result, Of how life beats you by default.
Has feathers but can't fly. Rests on legs but can't walk.
Before I grow I'm small. When I'm old I grow tall. When I die I give a mighty fall.