Riddle - what am i?!

I'll give you an answer to that old question "why!?"
And I'll tell you what happens after we die
I'll keep you in line and prey on your fears
I am the reason why the earth is in tears
Do as I say or I'll call you a whore
Abide by my rules or I'll start a new war
I say I'll bring peace on the wings of a dove
But I'll rip out the hearts of two men in love
I'm read all over in clear black and white
In the palm of your hand, the worlds greatest blight

what am i!?Www@Enter-QA@Com

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