Rav Yosef said: Yosef the Demon said to me: Ashmedai, the king of the demons, is appointed over all who perform actions in pairs, and a king is not called a harmful spirit. A king would not cause harm. Consequently, there is no reason to fear the harm of demons for having performed an action in pairs. Some say this statement in this manner: On the contrary, he is an angry king who does what he wants, as the halakha is that a king may breach the fence of an individual in order to form a path for himself, and none may protest his action. Similarly, the king of demons has full license to harm people who perform actions in pairs. Rav Pappa said: Yosef the Demon said to me: If one drinks two cups, we demons kill him; if he drinks four, we do not kill him. But this person who drank four, we harm him. There is another difference between two and four: With regard to one who drinks two, whether he did so unwittingly or intentionally, we harm him. With regard to one who drinks four, if he does so intentionally, yes, he is harmed; if he does so unwittingly, no, he will not be harmed. The Gemara asks: And if one forgets and it happens that he goes outside after having drunk an even number of cups, what is his solution? The Gemara answers: He should take his right thumb in his left hand, and his left thumb in his right hand, and say as follows: You, my thumbs, and I are three, which is not a pair. And if he hears a voice that says: You and I are four, which makes a pair, he should say to it: You and I are five. And if he hears it say: You and I are six, he should say to it: You and I are seven. The Gemara relates that there was an incident in which someone kept counting after the demon until he reached a hundred and one, and the demon burst in anger. Ameimar said: The chief of witches said to me: One who encounters witches should say this incantation: Hot feces in torn date baskets in your mouth, witches; may your hairs fall out because you use them for witchcraft; your crumbs, which you use for witchcraft, should scatter in the wind; your spices, which you use for your witchcraft, should scatter; the wind should carry away the fresh saffron that you witches hold to perform your witchcraft. As long as I was shown favor from Heaven and you showed me favor, I did not come here. Now that I have come here, your favor toward me has cooled and you should find favor. The Gemara relates that in the West, Eretz Yisrael, they were not particular with regard to pairs. Rav Dimi from Neharde’a was particular about pairs even with regard to the signs on a barrel; he would not write pairs of symbols on a barrel. There was an incident in which there were pairs of symbols on a barrel and the barrel burst. The Gemara concludes: The rule of the matter is that all who are particular about pairs, the demons are particular with him; and if one is not particular, they are not particular with him. However, one is required to be concerned about the harm that might result from purposely performing actions in pairs. When Rav Dimi came from Eretz Yisrael to Babylonia, he said: With regard to two eggs, two nuts, two cucumbers, and another matter, there is a halakha transmitted to Moses from Sinai that they are dangerous in pairs. But the Sages are uncertain about what the other matter is, and therefore the Sages decreed that all pairs are prohibited due to that other matter. And the Gemara notes that that which we said above, that the numbers ten, eight, six, and four do not cause the danger associated with pairs, we said only with regard to harmful spirits. However, with regard to witchcraft, we are concerned even with regard to one who performed an activity a greater number of times. This is like that incident involving a certain man who divorced his wife. She went and married a shopkeeper who sold wine in his store. Every day, the first husband would go and drink wine in that shop. His ex-wife would perform witchcraft upon him, and it would not be effective for her in her attempts to harm him because he was careful with regard to pairs. One day he drank a lot, and he did not know how much he drank. Until he drank sixteen cups, he was lucid and was careful with regard to himself, to keep track of how many cups he had drunk. From here onward he was not lucid and was not careful to watch himself, and she caused him to leave after having consumed a pair, i.e., an even number of cups. As he walked, a certain Arab met him and, noticing that he was bewitched, said to him: It is a dead man who walks here. He went and hugged a palm tree for support; the palm tree dried out due to the witchcraft, and he burst.