The reason we live

So much like a bird,
In the palm of your hand.
The best part of life,
An ungodly demand.

The world’s greatest men,
Have fallen at it’s touch.
From Hell some have risen,
While within it’s clutch.

It plays not favorites,
When making a choice.
And try as they may,
Listen to none’s voice.

And so it shall be,
Our main reason for life.
A four letter word,
That cuts like a knife.