The Darksword Trilogy by Margaret Weis

Born without the pervasive magic that sustains and defines his society, an outcast must confront prejudice, prophecy, and the mystery of his own origin when he discovers an ancient weapon capable of undoing the divine order. His quest to master that weapon draws together unlikely allies, forces him to face painful moral choices, and escalates into a battle with the gods and institutions that keep the world in stasis, ultimately forcing a wrenching decision about sacrifice, power, and what freedom will cost the people he loves.