The Sages taught: A person should not drink water at night. And if he drank, his blood is upon his own head, due to the danger. The Gemara asks: What is this danger? The Gemara answers: The danger of the shavrirei, an evil spirit that rules over water. And if he is thirsty, what is his remedy? If there is another person with him, he should wake him and say to him: I thirst for water, and then he may drink. And if there is no other person with him, he should knock with the lid on the jug and say to himself: So-and-so, son of so-and-so, your mother said to you to beware of the shavrirei verirei rirei yirei rei, found in white cups. This is an incantation against the evil spirit.
§ Abaye said: At first I would say that this halakha that one may not wash his hands with final waters over the ground is due to messiness. But the Master, Rabba, said to me that it is because an evil spirit rests upon the water and passersby are liable to be afflicted.
A Sage taught: If food and drink are under one’s bed, even if they are covered with iron vessels, an evil spirit rests upon them. The Sages taught: A person should not drink water on Tuesday nights or on Shabbat nights, i.e., Friday nights. And if he drinks water, his blood is upon his own head, due to the danger.
The Gemara asks: What is this danger?
The Gemara answers: The danger of the evil spirit that rules on these days. The Gemara asks: And if he is thirsty, what is his remedy? What should he drink? The Gemara answers: He should say the seven voices that David said over the water, and afterward he may drink. As it is stated: “The voice of the Lord is upon the waters; God of glory thunders, even the Lord upon many waters. The voice of the Lord is powerful; the voice of the Lord is full of majesty. The voice of the Lord breaks the cedars; the Lord breaks in pieces the cedars of Lebanon. He makes them also skip like a calf; Lebanon and Sirion like a young wild ox. The voice of the Lord hews out flames of fire. The voice of the Lord shakes the wilderness; the Lord shakes the wilderness of Kadesh. The voice of the Lord makes the hinds to calve, and strips the forests bare; and in His temple all say: Glory” (Psalms 29:3–9).
And if he does not remember that verse, he should say as follows: Lul, Shafan, Anigron, Anirdafin, which are names of demons, I sit between the stars, I walk between thin and fat people, take any of them if you wish but leave me alone.
And if he does not recall this incantation, if there is another person with him, he should wake him and say to him: So-and-so, son of so-and-so, I thirst for water; and then he may drink. And if there is no other person with him, he should knock the cover on the cup and then drink. And if he is not able to do this, he should throw some object in it and then drink.
The Sages taught: A person should not drink water from rivers or from ponds at night. And if he drank, his blood is upon his own head due to the danger. The Gemara explains: What is this danger? The danger of blindness. The Gemara asks: And if he is thirsty, what is his remedy? If there is another person with him, he should say to him: So-and-so, son of so-and-so, I thirst for water.
And if there is no one else with him, he should say to himself: So-and-so, my mother said to me to beware of shavrirei, the demon of blindness. He should continue to say the following incantation, in the first part of which the demon’s name gradually disappears: Shavrirei berirei rirei yiri ri; I thirst for water in white earthenware cups. This is an incantation against those demons.