Genesis 15:13 (KJV)

And he said, LORD God, whereby shall I know that I shall inherit it?

And he said unto him, Take me an heifer of three years old, and a she goat of three years old, and a ram of three years old, and a turtledove, and a young pigeon.

And he took unto him all these, and divided them in the midst, and laid each piece one against another: but the birds divided he not.

And when the fowls came down upon the carcases, Abram drove them away.

And when the sun was going down, a deep sleep fell upon Abram; and, lo, an horror of great darkness fell upon him.

And also that nation, whom they shall serve, will I judge: and afterward shall they come out with great substance.

And thou shalt go to thy fathers in peace; thou shalt be buried in a good old age.

But in the fourth generation they shall come hither again: for the iniquity of the Amorites is not yet full.

And it came to pass, that, when the sun went down, and it was dark, behold a smoking furnace, and a burning lamp that passed between those pieces.

In the same day the LORD made a covenant with Abram, saying, Unto thy seed have I given this land, from the river of Egypt unto the great river, the river Euphrates: