Cain & Abel, Hostile Brothers

Creatures you control have "Sacrifice this
Creature: Add one mana of any color"
Artifacts you control have
"{2},Sacrifice this Artifact: Draw a card"
Lands you control have "Sacrifice this Land:
You gain 3 Life"
Why are you incensed, and why is your face fallen?
For whether you offer well, or whether you do not,
at the tent flap sin crouches and for you is its longing,
but you will rule over it.- Genesis 4:1-18