Water of Jealousy
(The). If a woman was known to commit adultery she was to be stoned to death, according to the Mosaic law. (Deut. xxii. 22.) If, however, the husband had no proof, but only suspected his wife of infidelity, he might take her before the Sanhedrim to be examined, and if she denied it, she was given the “water of jealousy” to drink (Numb. v. 11-29). In this water some of the dust of the sanctuary was mixed, and the priest said to the woman, “If thou hast gone aside may Jehovah make this water bitter to thee, and bring on thee all the curses written in this law.” The priest then wrote on a roll the curses, blotted the writing with the water, gave it to the woman, and then handed to her the “water of jealousy” to drink.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894