“It is very easy, from this standpoint, to see how the notion arose that sacrifice was suffering.
While the divine life found its delight in exercising its activity of giving, and even when embodied in form cared not if the form perished by the giving, knowing it to be only its passing expression and the means of its separated growth; the form which felt its life forces pouring away from it cried out in anguish, and sought to exercise its activity in holding, thus resisting the outward flow.
The sacrifice diminished the life energies the form claimed as its own; or even entirely drained them away, leaving the form to perish.
In the lower world of forms this was the only aspect of sacrifice cognizable, and the form found itself driven to the slaughter, and cried out in fear and agony.
What wonder that men, blinded by form, identified sacrifice with the agonizing form instead of with the free life that gave itself, crying gladly: “Lo! I come to do thy will, O God; I am content to do it.””
Annie Besant
The Mark Of God: Understanding Your "I AM Presence" 