A mother is a powerful influence, a thought derived from this phrase’s completion: “is the hand that rules the world.” It comes from a poem by William Ross Wallace, “The Hand that Rules the World” (1865), and has been quoted ever since. A British schoolmistress’s change on it makes for a humorous mixed metaphor: “The hand that rocks the cradle kicked the bucket.” A more sinister interpretation is given in the 1992 motion picture The Hand That Rocks the Cradle, about a demented nanny seeking revenge for the death of her husband.