Genesis 4:9-11

Genesis 4:9-11

[9] And the LORD  said  unto Cain,  Where  is Abel  thy brother?  And he said,  I know  not: Am I my brother's  keeper?  [10] And he said,  What  hast thou done?  the voice  of thy brother's  blood  crieth  unto me from the ground.  [11] And now art thou cursed  from the earth,  which hath opened  her mouth  to receive  thy brother's  blood  from thy hand; 

What is the context of Genesis 4:9-11?