Midrash says Yitzchak sensed Yakum Ish Tzroros and Yosef Meshisa and they helped provide an impetus for giving the Brachos.
Out of all the Jews in history, why them? If you missed last year's idea, please check it out, as it's one of my all time favorites, that I have always taken tremendous chizuk from. Have a great Shabbos.
