What is Grendel's connection to cane and able?

Grendel's connection to cane and able is that cane killed able because he was jealous that he couldn't bring God the best of the Best that he worked for in life as an offering and able did Cain Got so fed up with this that he killed able out of pure evilness and Grendel kills man because he hate that man does so much wrong and still gets everything that Grendel doesn't have in life he feels lonely and alone all the time and man doesn't try and except him when he just merely wants someone to talk to someone he can relate to