The categories of work [forbidden on Shabbat] are forty less one: sowing, plowing, reaping, making sheaves, threshing, winnowing, picking the chaff from the grain, milling, sifting, kneading, baking, shearing, bleaching, hackling, dyeing, spinning, stretching the threads on the loom, making meshes, weaving, dividing, knotting, untying, sewing, tearing, trapping, slaughtering, skinning, salting hides, curing, scraping, cutting, writing, erasing, building, dismantling...