Genesis 15:12 (KJV)

And he said unto him, I am the LORD that brought thee out of Ur of the Chaldees, to give thee this land to inherit it.

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 he said unto Abram, Know of a surety that thy seed shall be a stranger in a land that is not their's, and shall serve them; and they shall afflict them four hundred years;

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.