The world began with a sacrifice.
That's how the ancestors saw it, 6000 years ago.
6000 years later, that's still how witches see it.
Throughout Indo-Europeandom (and beyond it as well), one finds tales of the Primal Sacrifice. A divine or semi-divine being is killed; from his body, the world as we know it is created.
And so sacrifice becomes the central rite of public worship. Every sacrifice reenacts—reembodies—that primal, cosmogonic sacrifice.
Every sacrifice recreates the world.
Moreover, this is a true story. Truly, life lives on life. No matter what kind of -vore you are, others die so that you can eat them and live.