Ketubot 23B

מתני׳ שתי נשים שנשבו, זאת אומרת ״נשביתי וטהורה אני״, וזאת אומרת ״נשביתי וטהורה אני״⁠ — אינן נאמנות. ובזמן שהן מעידות זו את זו ⁠— הרי אלו נאמנות.

Mishnah: In a case where witnesses testify that there are two women who were taken captive, and this woman says: I was taken captive but I am pure, and that woman says: I was taken captive but I am pure, they are not deemed credible. And when this woman testifies about that woman that she is pure and vice versa, they are deemed credible.

גמ׳ תנו רבנן: ״אני טמאה וחברתי טהורה״⁠ — נאמנת. ״אני טהורה וחברתי טמאה״⁠ — אינה נאמנת. ״אני וחברתי טמאה״⁠ — נאמנת על עצמה, ואינה נאמנת על חברתה. ״אני וחברתי טהורה״⁠ — נאמנת על חברתה, ואינה נאמנת על עצמה.

Talmud: A baraita states in the Tosefta (2:2): If one of the women says: I am tainted and my counterpart is pure, she is deemed credible on both counts. If she says: I am pure and my counterpart is tainted, she is not deemed credible with regard to herself nor with regard to her counterpart. If she says: I and my counterpart are both tainted, she is deemed credible with regard to herself but she is not deemed credible with regard to her counterpart. If she says: I and my counterpart are both pure, she is deemed credible with regard to her counterpart but she is not deemed credible with regard to herself.

אמר מר: ״אני טהורה וחברתי טמאה״⁠ — אינה נאמנת. היכי דמי? אי דליכא עדים, על עצמה אמאי לא מהימנא? ״נשביתי וטהורה אני״ קאמרה! אלא פשיטא דאיכא עדים.

The Master said in the baraita that if she says: I am pure and my counterpart is tainted, she is not deemed credible. The Talmud asks: What are the circumstances? If there are no witnesses that she was taken captive, why is she not deemed credible with regard to herself? If she is saying: I was taken captive and I am pure, she is deemed credible based on the principle that the mouth that prohibited is the mouth that permitted. Rather, it is obvious that there are witnesses that she was taken captive.