The early sages said: There have been four beautiful women in the world: Sarah, Avigail, Rachav, and Esther. Some of the sages thought that Esther was not beautiful, and so they replace her on the list of the world’s most beautiful women with Vashti. The early sages also said that one who mentions the name of Rachav will be filled with lustful urges and one who hears the voice of Yael will be filled with lustful urges. One who recalls Avigail will be filled with lustful urges, and one who sees Michal will be filled with lustful urges. One of the scholars, Rav Isaac, said that one who says “Rachav, Rachav” will immediately have a seminal emission due to sexual stimulation. Rav Nachman told him: I have tried it and said “Rachav, Rachav” yet I felt no sexual stimulation at all. Answer: When I said one says “Rachav, Rachav” I referred to those who knew her. Those men are so sexually stimulated that they have seminal emissions.
(Babylonian Talmud, Tractate Megillah 15a)