Bava Batra 41B

אתא לקמיה דרב יהודה. אזיל אייתי תרי סהדי, חד אמר: תרתי אוצייתא עאל, וחד אמר: תלת אוצייתא עאל. אמר ליה: זיל שלים תרתי מגו תלת.

Rav Kahana came before Rav Yehuda. Rav Kahana’s neighbor went and brought two witnesses. One said: Rav Kahana entered two rows into his neighbor’s land, and one said: Rav Kahana entered 3 rows into his neighbor’s land. Rav Yehuda said to Rav Kahana: Go and pay two out of the 3 that your neighbor is claiming by moving the wall two rows into your property.

אמר ליה: כמאן? כרבי שמעון בן אלעזר ⁠– דתניא, אמר רבי שמעון בן אלעזר: לא נחלקו בית שמאי ובית הלל על שתי כיתי עדים ⁠– שאחת אומרת מנה, ואחת אומרת מאתים ⁠– שיש בכלל מאתים מנה.

Rav Kahana said to Rav Yehuda: In accordance with whose opinion are you ruling that the testimony of witnesses who contradict each other is valid? Is it in accordance with the opinion of R' Shimon ben Elazar? As it is taught in a baraita that R' Shimon ben Elazar said: Beit Shammai and Beit Hillel did not disagree with regard to two sets of witnesses, where one set says that a litigant owes 100 dinars and one set says that he owes 200. In such a case, everyone agrees that 200 includes 100, and he is liable to pay 100.

על מה נחלקו? על כת אחת ⁠– שאחד אומר מנה, ואחד אומר מאתים; שבית שמאי אומרים: נחלקה עדותן, ובית הלל אומרים: יש בכלל מאתים מנה.

With regard to what did Beit Shammai and Beit Hillel disagree? They disagree with regard to one set of witnesses, where one witness says that a litigant owes 100 dinars and one witness says that he owes 200; as in such a case, Beit Shammai say that their testimony is divided, and they do not combine to form a set of witnesses, and Beit Hillel say that 200 includes 100, and they combine to form a set of witnesses. Rav Kahana assumed that Rav Yehuda based his ruling on R' Shimon ben Elazar’s interpretation of the opinion of Beit Hillel.