Genesis 15:9-11

"And he said unto him, Take me a heifer three years old, and a she-goat three years old, and a ram three years old, and a turtle dove, and a young pigeon. And he took all these, and divided them in the midst, and laid each half over against the other: but the birds divided he not. And the birds of prey came down upon the carcasses, and Abram drove them away."

The function of the slaughtered animals here was not that of a sacrifice, but of the ratification (confirmation) of a covenant. The ritual in view here was actually used in antiquity by numerous ancient people as the means of assuring the performance of agreements. There was no need whatever for God to do such a thing; and, evidently, it was prompted because of Abram's question as to how he might "really know" that he would inherit the land. The whole design is anthropomorphistic, God, in a vision, representing himself as taking an oath, in the manner of the ritual described, for the purpose of reassuring Abram. Psalms 110:4 speaks of God's swearing "with an oath" to raise up a priest forever after the order of Melchizedek. In such events, the heavenly Father condescends to assure men by the same devices by which men seek to reassure one another.

The animals here chosen, however, did not include an ass, as was used by the Amorites;[15] but they were clean creatures, later confirmed as suitable for sacrifices to God, as in the Law of Moses. That all of this was part of the vision, and not an actual happening, is confirmed in the truth that Abram did not pass between the carcasses, and that God did so only in a symbol. In the actual rituals, both parties passed through between the slain animals. Also note, that Abram did not need time to procure the creatures mentioned. It all took place in the vision.

"The birds of prey ... Abram drove them away ..." Christ himself used "the birds" as symbols of evil in the N.T. (Matthew 13:4); and they doubtless have the same symbolical meaning here. Morris suggested that: "They symbolized the efforts of Satan to thwart the plans of God."[16] Abram's watchfulness and his driving them away symbolize the need for Christians to be alert and aggressive in their opposition to evil.