Baal Shem Tov
The Baal Shem Tov was asked why the Amidah, the central prayer of the daily service, begins with "God of Abraham, God of Isaac, God of Jacob." Isn't that redundant? Why not just say "God of Abraham, Isaac, Jacob"? The Baal Shem Tov answered: "The God of Jacob was not the God of Issac, and the God of Isaac was not the God of Abraham. Each grasped God in his own way, and so must each of us. Only then will God's presence continue to dwell in this world.