Because, you have committed great sins -

If you ask me what proof I have for these words,

I say it is because I am the punishment of God -  

If you had not committed great sins, God would not have sent a punishment like me upon you -  Genghis Khan.

So?  Now you want revenge, then to be successful -

Revenge should be a considered and planned response enacted when the time is right, rather than a hasty and 'hot-blooded' action which will increase the chances of failure.  It should also never be remotely linked to you.