Genesis 15:13-16

13And he said to Abram, Know certainly that thy seed shall be a stranger in a land that is not theirs, and shall serve them; and they shall afflict them four hundred years; 14And also that nation, which they shall serve, will I judge: and afterward shall they come out with great substance. 15And thou shalt go to thy fathers in peace; thou shalt be buried in a good old age. 16But in the fourth generation they shall come here again: for the iniquity of the Amorites is not yet full.