volt (natsar, "to guard," "protest"): Isaiah's charge against Israel as "a people that .... lodge in the secret places" (Isa 65:4, margin "vaults," the King James Version "monuments") probably refers to the custom of sleeping in sacred tombs or vaults of idol temples to learn the future through dreams by the method known as incubation.
See DIVINATION, 6, (ii); 7, 1; FAMILIAR; WITCHCRAFT; and Expository Times, IX, 157 ff.