Sanhedrin 45B

תלמוד לומר: ״סקול יסקל״.

The verse states: “He should be stoned [sakol yissakel ],” with the doubled verb form indicating that the halakha applies in all places and at all times.

ואם לאו, עד השני נוטל את האבן. נוטל? והתניא: רבי שמעון בן אלעזר אומר, אבן היתה שם משוי שני בני אדם, נוטלה ונותנה על לבו. אם מת בה ⁠– יצא. וליטעמיך, תיקשי לך היא גופה: משוי שני בני אדם, נוטלה ונותנה על לבו?

§ The Mishnah teaches that if the condemned party does not die from his fall, the second witness takes the stone that had been prepared for this task and casts it on his chest. The Talmud asks: Does the witness take the stone by himself? But isn’t it taught in a baraita that R' Shimon ben Elazar says: A stone was there with a weight that could be lifted only by two men. The witness takes it and places, i.e., casts, it on the condemned party’s chest. If he dies with the casting of this stone, the obligation to stone the transgressor is fulfilled. This indicates that one individual could not lift the stone by himself. The Talmud answers: And according to your reasoning, the baraita itself should pose a difficulty for you, as it first states that the stone was of a weight that could be lifted only by two men, and then it says that the witness takes it and places it on the condemned party’s chest, apparently acting alone.

אלא, דמדלי לה בהדי חבריה, ושדי לה איהו, כי היכי דתיתי מרזיא.

Rather, both the Mishnah and the baraita should be explained as follows: The second witness lifts the stone together with the other witness, but then the second witness alone casts it so that it should fall with force upon the condemned party’s chest, as two people working together cannot aim their throw with precision.