Devarim 9:5

5 Not for thy tzedakah, or for the yosher (uprightness) of thine lev, dost thou go to possess their land; but for the wickedness of these Goyim Hashem Eloheicha doth drive them out from before thee, and that He may perform the word which Hashem swore unto Avoteicha, Avraham, Yitzchak, and Ya’akov.