When blind Isaac reached out to bless his son and said, "HaKol kol Yaakov v'ha-yadayim y'dei Esav" — "The voice is the voice of Jacob, but the hands are the hands of Esau" (Genesis 27:22) — he was speaking more than he knew.
The rabbis heard the whole of Jewish history folded into those eleven words.
The "voice of Jacob," they said, is the voice of lamentation. First it was the weeping caused when Hadrian massacred, at Alexandria in Egypt, twice the number of Jews who had come out under Moses. Then it was the weeping when Vespasian put to death in the city of Betar four hundred myriads — or, some say, four thousand myriads — of our people. When Jews cry, we cry with Jacob's voice. That is the inheritance.
"The hands are the hands of Esau," they continued, refers to the empires that descend from Esau: Rome and her daughters, whose hands destroyed our house, burned our Temple, and banished us from our land.
But the sages also read the verse in a different direction, and this reading is the sweeter one. There is no effective prayer, they said, that is not offered by the descendants of Jacob. And there is no winning battle that is not fought by the descendants of Esau.
Which is to say: the world is divided. Some peoples conquer with hands. Our people conquer, if we conquer at all, with the voice — with Torah, with liturgy, with weeping, with the long argument before God. Isaac's accidental blessing became a description of two different kinds of power, and Israel got the quieter one (Bereshit Rabbah 65:20; Gittin 57b).