If a married woman’s husband suspects she committed adultery and betrayed him but she denies doing so, she must be examined in the Holy Temple by drinking the holy waters. If she had committed adultery the water will cause her stomach to swell and her thighs to drop; if she had not committed adultery she will continue to live a healthy life and bear children. It is written in the Torah “If any man’s wife goes astray…and a man lies with her carnally…When he has made her drink the water, then it shall be, if she has defiled herself and behaved unfaithfully toward her husband, that the water that brings a curse will enter her and become bitter, and her belly will swell, her thigh will drop…But if the woman has not defiled herself, and is clean, then she shall be free and may conceive children.” The sages discussed the cases in which the test of the waters would not be efficacious and in which they were not reliable. Thus, for example, one sage argued that if there were witnesses who saw the woman committing adultery but the witnesses are abroad and so the court does not know of their existence, the waters will have no effect. It is possible that she did commit adultery and yet the waters which she drank will not cause her stomach to swell nor her thighs to drop. If, the scholars asked, in a case where there are witnesses somewhere in the world the waters are not effective, why did the sages rule that if, after the woman drank the waters, witnesses came forward her sacrifice must still be burned? We see that when she was drinking the waters there were witnesses somewhere, and so bringing her sacrifice was in error. Answer: The case in which the waters are effective even if witnesses come after the drinking is if the woman commits adultery an additional time in the Holy Temple and the witnesses come to testify about this act of adultery. The scholars then asked: How did she commit adultery in the Holy Temple? Don’t the young priests escort her throughout the ceremony of drinking the waters and bringing the sacrifice, guarding her so she will not commit adultery? Answer: She committed adultery with the young priests themselves. Another answer: The woman claimed that she had to go to the bathroom and it was there that she committed adultery.
(Babylonian Talmud, Tractate Sotah 6b)