According to Stephen Finlan:
In the premonarchic period, Hebrew sacrifice was not much different from that of its neighbors. Sacrifice was originally for appeasement, mollifying the gods with gifts ((The Background and Content of Paul's Cultic Atonement Metaphors , p. 29).It seems that one of the early notions underlying the concept of sacrifice was to "feed the god(s)." This is seen in the Hebrew Bible in Numbers 28:2-6 and in the more than 40 passages where the smell of the burnt-offering is said to be a "pleasant aroma" to Yahweh (the table of shewbread also depicted this element). As Finlan points out:
Theology is moving away from such anthropomorphic notions, but in the Pentateuch, it has not moved very far.... Feeding, housing, and mollifying a god, and praying in his direction, are only some of the naturalistic notions that occur in pagan and Hebrew traditions alike (p. 30).One of the developments in Hebrew theology was the idea that sin causes uncleanness or impurity. The sacrifices then become a means to effect purification. It appears that initially this was seen as some type of physical impurity that could be cleansed by blood and later the physical gave way to a spiritual interpretation of what was taking place. In the Hebrew mind, blood was an important purifying or cleansing agent. According to Finlan, The central feature becomes the sprinkling of blood instead of the sending up of smoke [as in the burnt-offering], and it is understood to purify rather than to appease (p. 40). James D. G. Dunn argues that in the Levitical sacrifices, God is never the object of the verb atone (כָּפַר), instead "sin" is the object. The sacrifice is seen as acting on the sin not on God directly. The key element of the sacrifice becomes the purging or removal of the uncleanness caused by sin (The Theology of Paul the Apostle, p. 214).
Leviticus 17:11 is a key text in understanding the signficance of the blood in the Hebrew mind. It reads: For the life of the flesh is in the blood, and I have given it for you on the altar to make atonement for your souls, for it is the blood that makes atonement by the life (ESV). The author is saying that the blood makes atonement because the life of a creature is in its blood. Finlan writes:
Manipulation of blood is effective because "the life of the flesh is in the blood"-- obviously (but not to us). The metaphysical logic that was obvious to the author and his readers was soon forgotten in the Jewish tradition. The text became normative, but its animistic assumptions were no longer understood.
Why should the sprinkling of life-force accomplish atonement? There is clearly some equivalency between blood and life, but the exact nature of the equivalency is not spelled out.... [Apparently] life is a force within the blood, and ritual, carefully performed, can harness this dangerous force. Blood, carrying the life-force, can somehow reverse the anti-life of sin and pollution. When the blood is poured on a ritually-polluted temple installation, the life-force cleans away the anti-life force, pollution (p. 41).
How the idea that blood has some special life force developed is not clear. It may be due to the fact that when the blood is removed, the life departs. We do know that this life principle being in the blood was not unique to the Hebrews. According to one conservative commentary on the Old Testament:
The idea that blood contained the essence of life is evidence in the Mesopotamian belief that the first people were created from the blood of a slain deity. But there were no dietary restrictions regarding blood and nothing to suggest a ritual use of blood, either in terms of what was offered to deity or in purification rituals, anywhere else in the ancient Near East (John Walton, Victor Matthews, and Mark Chavalas, The IVP Bible Background Commentary: Old Testament, , p. 132).
While the Hebrews may have been unique in the ANE in regard to their ritual use of the blood of the sacrifice, the notion of spilled blood as having expiatory effects was not unique. As De Maistre writes:
Let us accept the vitality of blood, or rather the identity of blood and life, as a fact which antiquity never doubted and which has been acknowledged again today; another opinion as old as the world itself was that heaven grew angry with the flesh, and blood could be appeased only by blood. No nation doubted that there was an expiatory virtue in the spilling of blood [emphasis mine](Ibid., p. 358).De Maistre maintains that the blood itself was of prime importance in the sacrificial ritual not the flesh or meat of the animal. He writes:
It is not at all merely a matter of a present, of an offering, of first-fruits, of a simple act of homage and recognition offered to the divine sovereign [...]; for on this supposition men would have sought in butcher shops the flesh that had to be offered on their altars [...]. It is a matter of blood; it is a matter of immolation properly speaking; it is a matter of explaining how men of all times and all places could agree in believing that there was, not in the offering of flesh (this must be noted carefully), but in the shedding of blood, an expiatory virtue (Ibid., p. 372).So, while all nations seemed to recognize the propitiatory power of sacrifices, the ritual use of the blood by the Hebrews indicates that they saw the blood as having magical, purifying power when applied. Finlan refers to the work of Jacob Milgrom (Studies in Cultic Theology and Terminology , pp. 38-43 and pp. 77-79):
Milgrom describes three different levels of purification to handle different levels of pollution: application of the blood of the sacrifice to the horns of the outer altar will purge the impurity caused by the voluntary sin of an individual; blood on the inner altar purges involuntary sin by the community; deliberate and wanton sin by either an individual or the community requires the sprinkling of blood on the kapporet [mercy seat], and can only be done once a year (pp. 32-33).
Initially, this purification by the application of the blood seems to have been taken in some kind of literalistic manner. Finlan argues:
And this reflects a truth about cultic ritual: cult takes the power of symbols literally. In fact, one could define cult as the systematic taking of religious symbols literally--as literal conduits of power. Inasmuch as it involves the belief that action upon the symbol will have an effect on the thing symbolized, cultic ceremony is inherently magical (p. 42).Later, of course, the literal understanding gives way to a spiritual interpretation of the practice. All of this becomes foundational to how the early Christians interpreted the death of Jesus.