Pesachim 12A

וחד מינייהו קטעי שעה ומשהו.

and one of them errs by an hour and a bit.

אזל רב הונא בריה דרב יהודה, אמרה לשמעתתא קמיה דרבא. אמר: ומה אילו דייקינן בהני סהדי, דהאי דקאמר שלש ⁠— בתחלת שלש, והאי דקאמר חמש ⁠— בסוף חמש, והויא עדות מוכחשת, ולא קטלינן, ואנן ניקום ונקטיל מספקא?! ורחמנא אמר: ״ושפטו העדה״ ״והצילו העדה״!

Rav Huna, son of Rav Yehuda, went and said the halakha of Abaye before Rava. Rava said to him that Abaye’s explanation must be rejected: And were we to closely examine the statements of these witnesses and ask them when precisely the incident occurred, and find that the one who says at 3 hours means that it occurred at the beginning of the 3rd hour, and the one who says at 5 hours means that it occurred at the end of the 5th hour, it would be contradictory testimony and we would not kill the accused on the basis of this testimony; and will we arise and kill based on uncertainty? Although their testimony could be valid, it could also be void. Can the court execute the accused based on that uncertainty? And consider that God says in the Torah: “And the congregation should judge…and the congregation should deliver” (Numbers 35:24–25), from which it is derived that judges must do everything in their power to save an accused from the death penalty.

אלא אמר רבא: לדברי רבי מאיר ⁠— אדם טועה שתי שעות חסר משהו; לדברי רבי יהודה ⁠— אדם טועה שלש שעות חסר משהו. לדברי רבי מאיר ⁠— אדם טועה שתי שעות חסר משהו, מעשה כי הוה, או בתחלת שתים או בסוף שלש, וחד מינייהו קטעי שתי שעות חסר משהו.

Rather, Rava said: In fact, according to the statement of R' Meir, a person errs by two hours less a bit; according to the statement of R' Yehuda, a person errs by 3 hours less a bit. The Talmud elaborates: According to the statement of R' Meir, a person errs by two hours less a bit. How so? When the incident occurred, it was either at the beginning of the 2nd hour or at the end of the 3rd hour and one of the witnesses erred by two hours less a bit, as that is a reasonable discrepancy.