In the OT the material events were ordered by Gods creative work in the law, covenants, statutes, decrees, curses and promises. When the sacrifice was instituted, it was a ceremony of violence and provision. The sacrifice was not only put to death but it was slaughtered. If the bodily act of sacrificing automatically forced God to bless the recipient in the gift then we could argue that Gods blessing is contained in a material object. But if it was an illustration of the eternal work of God that the blessing would come out of Gods pronouncements. This is why the pronouncement of cursing is illustrated in slaughtering the animal. So when prophets teach by illustrations they are pointing to Gods eternal pronouncements that are made from heaven to establish government. In some ways when the Prophets spoke the curses, they were inflicting the eternal violence of God that was demanded in slaughtering the animal.

 This is why the Psalmist carefully distinguishes between an acceptable sacrifice and an evil sacrifice. The distinguishing factor of an acceptable offering was in the Prophets practice of speaking the law, covenants, statutes, curses, etc. So we find this illustration used by God revealing to Abram He judges the nations taking the spoils blessing the offspring of Israel. We could say the sacrifice was not just a religious observance. But it was the striking illustration that God properly governs the heathen nations by overcoming their violent threats from His throne. God achieves this through the prophets who pronounce the curses upon law breakers. God had to overcome the senseless violence of the heathen nations to establish His covenant with Abraham. He overcomes them by a direct pronouncement from the mighty throne. He is teaching that Gods blessing is obtained by pushing the curse of the wicked underneath the feet of His prophets in the eternal curse of the law. The animal had to be slaughtered.