נשים
הלכות סוטה
פרק א

Halacha

הלכה א
קִנּוּי הָאָמוּר בַּתּוֹרָה (במדבר ה יד) "וְקִנֵּא אֶת אִשְׁתּוֹ" הוּא שֶׁיֹּאמַר לָהּ בִּפְנֵי עֵדִים אַל תִּסָּתְרִי עִם אִישׁ פְּלוֹנִי. אֲפִלּוּ הָיָה אָבִיהָ אוֹ אָחִיהָ אוֹ עַכּוּ''ם אוֹ עֶבֶד אוֹ שָׁחוּף הוּא הָאִישׁ שֶׁאֵינוֹ מִתְקַשֶּׁה וְאֵינוֹ מוֹלִיד:
כסף משנה
1.
The admonition of jealousy1קנא usually has the connotation of jealousy. There are, however, instances where it has the meaning "warning," as in Joel 2:18. stated in the Torah [Numbers 5:14], "And he will adjure his wife," means the following. He tells her in the presence of witnesses: "Do not enter into privacy with this and this man."
This applies even if the man [under suspicion] is her father, her brother, a gentile, a servant or a man who is impotent and incapable of having an erection or fathering a child.2The intent in all these examples is that it is unlikely that the woman would engage in adultery with such a man: the father and the brother because of the family connection, the gentile or the servant because we assume that a modest Jewish woman would not associate with such people, and the impotent man because of his physical condition. By citing such examples, the Rambam implies that surely such a warning can be given with regard to any ordinary man.

הלכה ב
הַסְּתִירָה הָאֲמוּרָה בַּתּוֹרָה (במדבר ה יג) "וְנִסְתְּרָה" הוּא שֶׁתִּסָּתֵר עִם אוֹתוֹ הָאִישׁ שֶׁאָמַר לָהּ אַל תִּסָּתְרִי עִמּוֹ בִּפְנֵי שְׁנֵי עֵדִים. אִם שָׁהֲתָה עִמּוֹ כְּדֵי טֻמְאָה שֶׁהוּא כְּדֵי לִצְלוֹת בֵּיצָה וּלְגָמְעָהּ הֲרֵי זוֹ אֲסוּרָה עַל בַּעְלָהּ עַד שֶׁתִּשְׁתֶּה מֵי הַמָּרִים וְיִבָּדֵק הַדָּבָר. וּבִזְמַן שֶׁאֵין שָׁם מֵי סוֹטָה תֵּאָסֵר עָלָיו לְעוֹלָם וְתֵצֵא בְּלֹא כְּתֻבָּה:
כסף משנה
2.
The term "enter into privacy" mentioned in the Torah [Ibid.:13] refers to entering into privacy with the man concerning whom she was warned, in the presence of two witnesses, not to enter into privacy.3These can be the same two witnesses in whose presence the warning was administered (Hilchot Edut 21:5).
If she remains with him long enough to engage in relations - i.e., the amount of time necessary to roast an egg and swallow it,4We suspect that she committed adultery. she is forbidden to her husband5As stated in Hilchot Gerushin 11:14, a woman who commits adultery is forbidden to her husband. Since we suspect that this woman committed adultery, she is forbidden until her faithfulness is proven. until she drinks the bitter water, and [her faithfulness] is checked. In an era when [the probe of] the waters of the sotah is unavailable, she is forbidden to her husband forever and is divorced without receiving the [money due her by virtue of] her ketubah.6For it is her immodest behavior that caused her to become forbidden (Hilchot Ishut 24:24).

הלכה ג
קִנֵּא לָהּ עַל שְׁנַיִם כְּאֶחָד וְאָמַר לָהּ אַל תִּסָּתְרִי עִם פְּלוֹנִי וּפְלוֹנִי. וְנִסְתְּרָה עִם שְׁנֵיהֶן כְּאֶחָד וְשָׁהֲתָה כְּדֵי טֻמְאָה. אֲפִלּוּ הֵם שְׁנֵי אַחֶיהָ אוֹ אָבִיהָ וְאָחִיהָ הֲרֵי זוֹ אֲסוּרָה עַד שֶׁתִּשְׁתֶּה:
כסף משנה
3.
If [a husband] warns his wife with regard to two men at the same time, telling her: "Do not enter into privacy with so and so, and so and so," she is forbidden [to her husband] until she drinks [the waters] if she enters into privacy with the two men at the same time,7Even though in general a woman is allowed to enter into privacy with two men of established moral standing, in this instance, since the husband expressed his disapproval, such an act warrants drinking the bitter water. and remains there long enough to engage in relations. [This applies] even if [the two men] are her two brothers or her father and her brother.

הלכה ד
אָמַר לָהּ בִּפְנֵי שְׁנַיִם אַל תְּדַבְּרִי עִם פְּלוֹנִי אֵין זֶה קִנּוּי. וְאַף עַל פִּי שֶׁנִּסְתְּרָה עִמּוֹ בְּעֵדִים וְשָׁהֲתָה כְּדֵי טֻמְאָה לֹא נֶאֶסְרָה עָלָיו וְאֵינָהּ שׁוֹתָה בְּקִנּוּי זֶה:
כסף משנה
4.
If he told her in the presence of two [men]: "Do not speak to so and so," this is not considered to be a warning. Even if she enters into privacy with him in the presence of witnesses and remains there long enough to engage in relations, she is not forbidden to [her husband], nor can she be required to drink [the bitter water] because of such a warning.

הלכה ה
וְכֵן אִם אָמַר לָהּ אַל תִּסָּתְרִי עִמּוֹ וְרָאוּהָ מְדַבֶּרֶת עִמּוֹ אֵין זוֹ סְתִירָה. וְלֹא נֶאֶסְרָה וְלֹא שׁוֹתָה. וְכֵן אִם לֹא קָדַם קִנּוּי וּבָאוּ שְׁנַיִם וְהֵעִידוּ שֶׁנִּסְתְּרָה עִם זֶה וְשָׁהֲתָה כְּדֵי טֻמְאָה לֹא נֶאֶסְרָה עַל בַּעְלָהּ וְאֵינָהּ שׁוֹתָה:
כסף משנה
5.
Similarly, if he told her, "Do not enter into privacy with him," and witnesses saw her speaking with him, she is not considered to be having entered into privacy. She is not forbidden to [her husband], nor can she be required to drink [the bitter water].
Similarly, if she was not warned at all, and two witnesses came and testified that she entered into privacy with a man and remained long enough to engage in relations, she is not forbidden to [her husband],8Entering into privacy (yichud) with another man is forbidden (Hilchot Issurei Bi'ah, ch. 22). Nevertheless, Kiddushin 81a states that as long as a warning was not given, such an act is not sufficient cause for a woman to be forbidden to her husband. nor can she be required to drink [the bitter water].

הלכה ו
אָמַר לָהּ לֹא תִּסָּתְרִי עִם אִישׁ פְּלוֹנִי וְהָיָה קָטָן פָּחוֹת מִבֶּן תֵּשַׁע שָׁנִים וְיוֹם אֶחָד. אוֹ שֶׁאָמַר לָהּ אַל תִּסָּתְרִי עִם בְּהֵמָה זוֹ אֵין זֶה קִנּוּי שֶׁנֶּאֱמַר (במדבר ה יג) "וְשָׁכַב אִישׁ אֹתָהּ" פְּרָט לְקָטָן וְלִבְהֵמָה שֶׁאֵין אוֹסְרִין אוֹתָהּ עָלָיו:
כסף משנה
6.
If he told her: "Do not enter into privacy with so and so," and named a boy below the age of nine,"9Implied is that the warning is effective after a boy reaches the age of nine, for from the age of nine a boy is fit to engage in sexual relations, as explained in Hilchot Ishut 11:3. Rav Ovadiah of Bertinoro (Sotah 4:4) differs and maintains that a youth must attain majority before a warning is effective. There are several Midrashic sources for the Rambam's ruling. or he told her: "Do not enter into privacy with this animal," this is not a [binding] warning.
[These laws are derived as follows:] The Torah [ibid.] states: "And a man had relations with her." This excludes a minor and an animal. She is not forbidden to her husband because of them.

הלכה ז
בַּעַל שֶׁמָּחַל עַל קִנּוּיוֹ קֹדֶם שֶׁתִּסָּתֵר קִנּוּיוֹ מָחוּל וּכְאִלּוּ לֹא קִנֵּא לָהּ מֵעוֹלָם. אֲבָל אִם מָחַל אַחַר שֶׁתִּסָּתֵר אֵינוֹ יָכוֹל לִמְחל. גֵּרְשָׁהּ הֲרֵי זֶה כְּמִי שֶׁמָּחַל וְאִם הֶחֱזִירָהּ צָרִיךְ לְקַנְּאוֹת קִנּוּי אַחֵר:
כסף משנה
7.
When a husband forgoes a warning before his wife enters into privacy with [the man in question], the warning is nullified, and it is as if he had never issued a warning to her [regarding him]. If, however, he forgoes the warning after she enters into privacy with him, the warning cannot be nullified.10And she must drink the bitter water.
The rationale for this ruling is that as long as the woman has not entered into privacy with the other man, the husband's warning has not been reinforced by her conduct. Accordingly, since he has authority over his warning, he can withdraw it. When, however, she has already entered into privacy with the other man, she is already required by the Torah to drink the bitter water. Her husband has no authority over the Torah's requirement, and thus, he can no longer withdraw his warning (Likkutei Sichos, Vol. IV). See also the gloss of the Tzafnat Paneach to this halachah.

If he divorces his wife, it is as if he has nullified the warning. If he remarries her, he must issue a second warning [for her to be bound by it].

הלכה ח
קִנֵּא לָהּ בִּפְנֵי שְׁנַיִם וְרָאָה אוֹתָהּ שֶׁנִּסְתְּרָה עִם זֶה שֶׁקִּנֵּא לָהּ עָלָיו וְשָׁהֲתָה כְּדֵי טֻמְאָה הֲרֵי זוֹ אֲסוּרָה עָלָיו וְיוֹצִיא וְיִתֵּן כְּתֻבָּה. שֶׁאֵינוֹ יָכוֹל לְהַשְׁקוֹתָהּ עַל פִּי עַצְמוֹ. וְכֵן אִם שָׁמַע הָעָם מְרַנְּנִין אַחֲרֶיהָ אַחַר הַקִּנּוּי וְהַסְּתִירָה עַד שֶׁשָּׁמַע מֵהַנָּשִׁים הַטּוֹוֹת לְאוֹר הַלְּבָנָה נוֹשְׂאוֹת וְנוֹתְנוֹת בָּהּ שֶׁזִּנְּתָה עִם הָאִישׁ שֶׁקִּנֵּא לָהּ עָלָיו הֲרֵי זֶה אָסוּר לְקַיְּמָהּ וְיוֹצִיא וְיִתֵּן כְּתֻבָּה:
כסף משנה
8.
If [the husband] issued a warning to [his wife] in the presence of two [witnesses] and then saw her enter into privacy with the man concerning whom she was warned, and she remained long enough to engage in relations, she becomes forbidden to him. He must divorce her and pay her [the money due her by virtue of her] ketubah.11In this instance, the husband is required to pay his wife the money due her by virtue of her ketubah because, although he is bound by the evidence of his own eyes, it is not sufficient to require his wife to drink the bitter water. For that, the testimony of two witnesses is necessary.
Similarly, if he hears people gossiping about her after she has been warned, that she entered into privacy with the man in question, to the extent that the women who weave at night by the moonlight chatter about her, saying that she committed adultery with the man concerning whom she has been warned, her husband is forbidden to remain married to her and must instead divorce her and pay her [the money due her by virtue of] her ketubah.12The Rambam is speaking about an instance when, despite the gossip generated about the woman, there is no (or only one) witness who can testify about her entering into privacy with the man involved. Hence, because of her immodest conduct, he must divorce her. He must, however, pay the money due her by virtue of her ketubah, because, as stated in Sotah 6b, the bitter water will not test the chastity of a woman whose immodest conduct has become public knowledge.

הלכה ט
בָּא עֵד אֶחָד וְהֵעִיד לוֹ שֶׁנִּסְתְּרָה עִמּוֹ אַחַר קִנּוּי וְשָׁהֲתָה כְּדֵי טֻמְאָה. אִם הוּא נֶאֱמָן לוֹ וְדַעְתּוֹ סוֹמֶכֶת עָלָיו יוֹצִיא וְיִתֵּן כְּתֻבָּה. וְאִם לָאו הֲרֵי אִשְׁתּוֹ מֻתֶּרֶת לוֹ:
כסף משנה
9.
[The following rules apply when] one witness comes and testifies that, after a warning was issued, she entered into privacy with the man concerning whom she was warned and remained long enough to engage in relations. If [the husband] considers [the witness] to be faithful, and he relies on him, he must divorce her and pay her [the money due her by virtue of] her ketubah.13Since the testimony of one witness is not sufficient to require her to drink the bitter water, and yet the husband relies on the testimony of the witness, she is forbidden to the husband, but he must bear the financial burden of the prohibition. (See Hilchot Ishut 24:17.) If [he does] not [rely on that person], his wife remains permitted to him.14For a woman does not become forbidden until two witnesses testify that she entered into privacy with the man in question.

הלכה י
וְאֵלּוּ שֶׁבֵּית דִּין מְקַנִּין לָהֶן. מִי שֶׁנִּתְחָרֵשׁ בַּעְלָהּ אוֹ שֶׁנִּשְׁתַּטָּה אוֹ שֶׁהָיָה בִּמְדִינָה אַחֶרֶת אוֹ שֶׁהָיָה חָבוּשׁ בְּבֵית הָאֲסוּרִין. לֹא לְהַשְׁקוֹתָהּ אֶלָּא לְפָסְלָהּ מִכְּתֻבָּתָהּ:
כסף משנה
10.
The court should issue a warning to the following women [who are suspected of immodest behavior]: a woman whose husband has become a deaf-mute or has lost control of his mental faculties, one whose husband is overseas or one whose husband is imprisoned. The intent is not to have [such a woman] drink [the bitter water],15For that is possible only when a warning was administered by the husband, as stated in the following halachah. but rather to disqualify her from receiving [the money due her by virtue of] her ketubah.16Since the men in question are incapable of acting on their own, the court takes the initiative on their behalf. The court's action has two objectives: to maintain the moral standard of the Jewish people, and if that fails, to protect the husband's interest and cause a woman who acts immodestly to pay the penalty for her conduct.

הלכה יא
כֵּיצַד. שָׁמְעוּ בֵּית דִּין שֶׁהָעָם מְרַנְּנִין אַחֲרֶיהָ. קוֹרְאִין אוֹתָהּ וְאוֹמְרִין לָהּ אַל תִּסָּתְרִי עִם אִישׁ פְּלוֹנִי. בָּאוּ עֵדִים אַחַר כָּךְ שֶׁנִּסְתְּרָה עִמּוֹ וְשָׁהֲתָה כְּדֵי טֻמְאָה בֵּית דִּין אוֹסְרִין אוֹתָהּ עַל בַּעְלָהּ לְעוֹלָם וְקוֹרְעִין כְּתֻבָּתָהּ. וּכְשֶׁיָּבוֹא בַּעְלָהּ אוֹ יַבְרִיא אוֹ יָצָא מִבֵּית הָאֲסוּרִין נוֹתֵן לָהּ גֵּט. וְאֵינוֹ יָכוֹל לְהַשְׁקוֹתָהּ מִפְּנֵי שֶׁלֹּא קִנֵּא לָהּ הוּא:
כסף משנה
11.
What is implied? If the court hears that people are gossiping about [a particular woman], they call her and tell her: "Do not enter into privacy with so and so." If witnesses come afterwards and testify that she entered into privacy with the man concerning whom she was warned, and remained long enough to engage in relations, the court prohibits her [from engaging in relations] with her husband forever and tears up her marriage contract.
When her husband returns, regains his health or is released from prison, he must give her a get.17From the commentaries, it appears that he is required to do so; he does not have an option. He cannot require her to drink [the bitter water], because he did not administer the warning himself.

הלכה יב
שָׁתָת מֵי הַמָּרִים וְנִקְּתָה מֵהֶן וְחָזַר וְקִנֵּא לָהּ עִם הָאִישׁ שֶׁהִשְׁקָה עַל יָדוֹ וְנִסְתְּרָה עִמּוֹ אֵינוֹ יָכוֹל לְהַשְׁקוֹתָהּ עַל יָדוֹ פַּעַם שְׁנִיָּה אֶלָּא תֵּאָסֵר עָלָיו לְעוֹלָם וְתֵצֵא בְּלֹא כְּתֻבָּה. אֲבָל אִם קִנֵּא לָהּ עִם אַחֵר וְנִסְתְּרָה עִם הָאַחֵר בְּעֵדִים מַשְׁקִין אוֹתָהּ פַּעַם שְׁנִיָּה וַאֲפִלּוּ כַּמָּה פְּעָמִים. וְהוּא שֶׁיַּשְׁקֶה אוֹתָהּ בְּכָל פַּעַם בִּגְלַל אִישׁ אַחֵר:
כסף משנה
12.
[The following rules apply if a woman was required to] drink the bitter water [because of her husband's suspicion of a particular man] and did not die as a result of it, and afterwards, her husband gave her a warning with regard to that same man. If she enters into privacy with him, he cannot make her drink because of him a second time. Instead, she becomes forbidden to her husband forever and must be divorced without receiving [the money due her by virtue of] her ketubah.18In this instance as well, entering into privacy with the man is considered an immodest act, sufficient cause for the woman to forfeit the money due her by virtue of her ketubah.
If, however, her husband issued a warning to her regarding another man, and she entered into privacy with him in the presence of witnesses, she can be forced to drink the waters again. Indeed, this can happen several times, provided each time her husband has her drink because of another man.

הלכה יג
הִשְׁקָה אוֹתָהּ וְגֵרְשָׁהּ וְנִשֵּׂאת לְאַחֵר וְקִנֵּא לָהּ עִם הָאִישׁ שֶׁהִשְׁקָה אוֹתָהּ הַבַּעַל הָרִאשׁוֹן בִּגְלָלוֹ וְנִסְתְּרָה עִמּוֹ בְּעֵדִים. הֲרֵי הַבַּעַל הַשֵּׁנִי מַשְׁקֶה אוֹתָהּ עַל יָדוֹ מִפְּנֵי שֶׁהוּא בַּעַל שֵׁנִי. וַאֲפִלּוּ מֵאָה וְנִשֵּׂאת לְזֶה אַחַר זֶה מַשְׁקִין אוֹתָהּ עַל יְדֵי אִישׁ אֶחָד. וְאֵין אוֹמְרִין וַדַּאי שֶׁהֻחְזְקָה לָזֶה וּטְמֵאָה עַד שֶׁיִּהְיֶה שָׁם עֵד:
כסף משנה
13.
If a woman's husband had her drink [the bitter water] because of a specific man and then divorced her and she remarried, her second husband can issue a warning to her with regard to the same man. If she enters into privacy with him, her husband can make her drink [the bitter water], because he is her second husband. Even if a hundred men married this woman one after the other, they can all have her drink [the bitter water] because of this same man.

הלכה יד
הָאִשָּׁה שֶׁקִּנֵּא לָהּ בַּעְלָהּ וְנִסְתְּרָה אַחַר הַקִּנּוּי עִמּוֹ בְּעֵדִים וַהֲרֵי הִיא עוֹמֶדֶת לִשְׁתּוֹת וּבָא עֵד אֶחָד וְהֵעִיד עָלֶיהָ שֶׁנִּבְעֲלָה בְּפָנָיו עִם זֶה שֶׁקִּנֵּא לָהּ עִמּוֹ הֲרֵי זֶה אֲסוּרָה עַל בַּעְלָהּ לְעוֹלָם. וְאֵינָהּ שׁוֹתָה וְיוֹצֵאת בְּלֹא כְּתֻבָּה. וַאֲפִלּוּ הָיָה עֵד טֻמְאָה זֶה אֶחָד מֵעֵדֵי הַסְּתִירָה שֶׁנֶּאֱמַר (במדבר ה יג) "וְעֵד אֵין בָּהּ" וַהֲרֵי כָּאן עֵד:
כסף משנה
14.
[The following laws apply if] a woman was warned by her husband and then entered into privacy [with the man in question] after the warning, thus causing her to be required to drink [the bitter water]. If [even] one witness comes and states that she engaged in sexual relations with the man regarding whom she was warned in his presence, the woman is forbidden to her husband forever. She may not drink [the bitter water],19Even if she desires to in an attempt to prove her innocence. and must be divorced without receiving [the money due her by virtue of] her ketubah. This applies even if the witness who testifies concerning her adultery is also one of the witnesses who testifies that she entered into privacy with [the man regarding whom she was warned].20If, however, the other witness who saw the man and the woman enter into privacy says that they did not engage in relations, the woman does not forfeit the money due her by virtue of her ketubah (Beit Shmuel 178:12).
[This ruling is derived from Numbers 5:13]: "There is no witness against her."21Implied is that even if there is one witness, she is not to be tested by the bitter water. Generally, the Torah requires two witnesses for all matters involving marital law (Sotah 31b). In this case, an exception was made because the fact that a warning was issued and disobeyed is an indication of immodesty.

הלכה טו
אֲפִלּוּ אִשָּׁה וְעֶבֶד וְשִׁפְחָה וּפָסוּל לְעֵדוּת בַּעֲבֵרָה מִדִּבְרֵי סוֹפְרִים וַאֲפִלּוּ קָרוֹב נֶאֱמָן לְעֵדוּת סוֹטָה לְהָעִיד עָלֶיהָ שֶׁזִּנְּתָה וְתֵאָסֵר עַל בַּעְלָהּ לְעוֹלָם. וְאֵינָהּ שׁוֹתָה וְתֵצֵא בְּלֹא כְּתֻבָּה. הוֹאִיל וְקָדַם הַקִּנּוּי וְהַסְּתִירָה בְּעֵדִים כְּשֵׁרִים וְהַתּוֹרָה הֶאֱמִינָה עֵד אֶחָד בְּטֻמְאָה הֲרֵי כֻּלָּן כְּשֵׁרִין לְעֵדוּת טֻמְאָה. אַף חָמֵשׁ נָשִׁים שֶׁשּׂוֹנְאוֹת זוֹ אֶת זוֹ מְעִידוֹת זוֹ עַל זוֹ לוֹמַר שֶׁנִּטְמֵאת. וְנֶאֱמֶנֶת עָלֶיהָ לְאָסְרָהּ עַל בַּעְלָהּ וְשֶׁלֹּא לְהַשְׁקוֹתָהּ. אֲבָל לֹא לְהַפְסִידָהּ מִכְּתֻבָּתָהּ. אֶלָּא נוֹטֶלֶת כְּתֻבָּתָהּ וְיוֹצְאָה:
כסף משנה
15.
Even a woman, a servant, a maid-servant or someone disqualified from testifying because of [the transgression of] a Rabbinic prohibition, and even a relative,22All the individuals mentioned are normally not accepted as witnesses. Nevertheless, an exception is made in this instance, as the Rambam explains. The testimony of witnesses who have violated prohibitions of Scriptural origin is not accepted, because we suspect that they will lie. may testify with regard to a woman suspected of infidelity, saying that she committed adultery. This causes her to be forbidden to her husband forever, to be prevented from drinking [the bitter water] and to be divorced without receiving [the money due her by virtue of] her ketubah.
[The rationale is] that since the Torah accepts the testimony of one witness with regard to [the woman's] adultery [we see that the formal laws of testimony do not apply]. Therefore, anyone's testimony is accepted with regard to this matter.
Even the five women who we assume hate each other23As stated in Hilchot Gerushin 12:16, these women are the woman's mother-in-law, her mother-in-law's daughter, her husband's other wife, her yevamah and her husband's daughter from another marriage. can offer testimony regarding each other,24The Rambam's wording refers to the following concept. Generally, because of the bad feelings that characterize the relationship between these pairs, testimony is also disqualified in the reverse of the above situations. For example, if the husband of the daughter of a woman's husband is missing, the woman may not testify about the matter, although she has no natural reason to hate the other woman. saying that they committed adultery [in these circumstances]. Their testimony is accepted with regard to causing her to be forbidden to her husband and not [to compel her] to drink [the bitter water]. It is not a sufficient basis to cause her to forfeit [the money due her by virtue of] her ketubah. Instead, she collects [the money due her by virtue of] her ketubah and leaves [his household].25The testimony of these women is accepted because through it, the woman is granted the money due her by virtue of her ketubah. We assume that these women would desire to discredit her entirely and cause her to forfeit this money. Since without their testimony, the woman is forbidden to her husband until she drinks the bitter water and forfeits the money due her by virtue of her ketubah, their testimony abets her position rather than harms it. (Indeed, note the gloss of Rabbi Akiva Eiger, who questions why the testimony of these women is accepted at all.)

הלכה טז
בָּא עֵד אֶחָד כָּשֵׁר וְאָמַר נִטְמֵאת הֲרֵי זוֹ אֵינָהּ שׁוֹתָה כְּמוֹ שֶׁבֵּאַרְנוּ. בָּא עֵד אֶחָד וְהִכְחִישׁוֹ וְאָמַר לֹא נִטְמֵאת אֵין שׁוֹמְעִין לוֹ. שֶׁעֵד אֶחָד בְּטֻמְאַת סוֹטָה כִּשְׁנַיִם. וְאֵין דְּבָרָיו שֶׁל אַחֲרוֹן דּוֹחִין דִּבְרֵי הָרִאשׁוֹן שֶׁהוּא כִּשְׁנַיִם:
כסף משנה
16.
If one acceptable witness comes and says that the woman committed adultery, she is not required to drink [the bitter water], as we stated. If another witness comes and contradicts his testimony, saying: "She did not commit adultery," the statements [of the second witness] are disregarded.26In most instances, when the statements of one witness are countered by the statements of another, the two are considered to be of equal weight, and thus the statements of the first witness are no longer considered.
[The rationale is] with regard to a sotah, [the testimony of] one witness is considered equivalent to [that of] two [witnesses in ordinary matters]. Thus, the testimony of the second witness cannot nullify the testimony of the first witness, which is considered to be equivalent to [that of] two witnesses.27This principle applies not only with regard to a sotah, but with regard to all instances in which one witness's testimony is considered equivalent to that of two witnesses (Sotah 31b) - e.g., testimony regarding the death of a woman's husband (Hilchot Gerushin 12:18).

הלכה יז
בָּאוּ שְׁנֵיהֶן כְּאֶחָד זֶה אוֹמֵר נִטְמֵאת וְזֶה אוֹמֵר לֹא נִטְמֵאת. אוֹ שֶׁאָמַר אֶחָד נִטְמֵאת וּבָאוּ שְׁנַיִם אֲחֵרִים וְאָמְרוּ לֹא נִטְמֵאת הֲרֵי זוֹ שׁוֹתָה:
כסף משנה
17.
If, however, both come at the same time28I.e., one testified directly after the other. and one says: "She committed adultery," and the other says, "She did not commit adultery,"29Since the testimony of the first witness was never established, it is not given more weight than it would ordinarily. Since the woman's fidelity is in doubt, she is required to drink the bitter water. The principles in this and the following halachot are paralleled in Hilchot Gerushin, Chapter 12. or one says: "She committed adultery," and two others say, "She did not commit adultery,"30In this instance, the testimony of the pair of witnesses balances the testimony of the witness who said that she committed adultery, even if that witness's testimony had already been established in court. she must drink [the bitter water].

הלכה יח
בָּא עֵד אֶחָד כָּשֵׁר וְנָשִׁים רַבּוֹת אוֹ פְּסוּלִין רַבִּים כְּאֶחָד. הָעֵד אוֹמֵר נִטְמֵאת וְהַנָּשִׁים אוֹ הַפְּסוּלִין אוֹמְרִים לֹא נִטְמֵאת הֲרֵי זוֹ שׁוֹתָה. שֶׁעֵד אֶחָד וּפְסוּלִין רַבִּים כְּמֶחֱצָה עַל מֶחֱצָה הֵם:
כסף משנה
18.
When one acceptable witness and many women or unacceptable witnesses come at the same time, and the acceptable witness says that the woman committed adultery, while the women or the unacceptable witnesses say that she did not, she is required to drink [the bitter water].31Compare to Hilchot Rotzeach USh'mirat HaNefesh 9:16. [The rationale is that the testimony of] one acceptable witness and [that of] many unacceptable witnesses are considered to be of equal weight.

הלכה יט
הָיוּ כֻּלָּן פְּסוּלִין הַלֵּךְ אַחַר הָרֹב. כֵּיצַד. שְׁתֵּי נָשִׁים אוֹמְרוֹת נִטְמֵאת וְשָׁלֹשׁ אוֹמְרוֹת לֹא נִטְמֵאת הֲרֵי זוֹ שׁוֹתָה. שָׁלֹשׁ אוֹמְרוֹת לֹא נִטְמֵאת וְאַרְבַּע אוֹמְרוֹת נִטְמֵאת הֲרֵי זוֹ אֵינָהּ שׁוֹתָה. הָיוּ מֶחֱצָה עַל מֶחֱצָה הֲרֵי זוֹ שׁוֹתָה:
כסף משנה
19.
If all the witnesses are unacceptable, the ruling depends on the majority.
What is implied? If two women say she committed adultery, and three say she did not, she must drink [the bitter water]. If three say she did not commit adultery and four say that she did, she is not required to drink. If an equal number of women espouse each position, she must drink [the waters].32Since the woman's fidelity remains in doubt, she must drink the waters to clarify the situation.

הלכה כ
כָּל סוֹטָה שֶׁאָמַרְנוּ שֶׁאֵינָהּ שׁוֹתָה מִפְּנֵי עֵדֵי טֻמְאָה הֲרֵי זוֹ אֲסוּרָה עַל בַּעְלָהּ לְעוֹלָם וְתֵצֵא בְּלֹא כְּתֻבָּה שֶׁהֲרֵי נֶאֶסְרָה בְּקִנּוּי וּסְתִירָה. וְהַשְּׁתִיָּה שֶׁתַּתִּירָהּ נִמְנְעָה שֶׁהֲרֵי יֵשׁ בָּהּ עֵד כְּמוֹ שֶׁבֵּאַרְנוּ:
כסף משנה
20.
In all instances that we said that a sotah should not drink [the waters] because of testimony that she committed adultery, she is forbidden to her husband forever and must be divorced without receiving [the money due her by virtue of] her ketubah, for she was forbidden because [she received a] warning and entered into privacy [with the said man]. And she is prevented from drinking the waters, [which could] cause her [to be] permitted, because of the presence of the witness, as we explained.33See Halachah 14.

נשים הלכות סוטה פרק א
Nashim Sotah Chapter 1