Nicene and Post-Nicene Fathers, Vol. II:
City of God: Chapter 4

Chapter 4.—That Sacrifice is Due to the True God Only.

But, putting aside for the present the other religious services with which God is worshipped, certainly no man would dare to say that sacrifice is due to any but God.  Many parts, indeed, of divine worship are unduly used in showing honor to men, whether through an excessive humility or pernicious flattery; yet, while this is done, those persons who are thus worshipped and venerated, or even adored, are reckoned no more than human; and who ever thought of sacrificing save to one whom he knew, supposed, or feigned to be a god?  And how ancient a part of God’s worship sacrifice is, those two p. 183 brothers, Cain and Abel, sufficiently show, of whom God rejected the elder’s sacrifice, and looked favorably on the younger’s.