Cain And Abel

Cain said to Abel his brother, "Let us go out to the field." And when they were in the field, Cain rose up against his brother Abel, and killed him. Then the LORD said to Cain, "Where is Abel your brother?"  He said, "I do not know; am I my brother's keeper?"  And the LORD said, "What have you done? The voice of your brother's blood is crying to me from the ground."