Tzimtzum is the founding move of Lurianic Kabbalah and the strangest thing Judaism asserts about God. Isaac Luria, teaching in Safed in the early 1570s and dead at thirty-eight, described the Infinite contracting from a point to leave a space where something other than God could exist, then sending light into vessels that could not hold it and shattered. Divine sparks fell into the husks of the material world, and the work of every commandment is to raise one — which is how tikkun, repair, entered the vocabulary it now lives in. Hasidism took the doctrine toward panentheism: nothing exists but God and the world is an appearance. The Vilna Gaon and the Lithuanian schools read tzimtzum figuratively and treated the literal reading as heresy; the excommunication of 1772 was partly about exactly this. Jews who have never heard the word use its vocabulary weekly, because tikkun olam came out of it.