דיני נפשות מתחילין מן הצד: מנא הני מילי אמר ר' אחא בר פפא אמר קרא (שמות כג, ב) לא תענה על ריב לא תענה על רב
The mishna teaches that in cases of capital law, the judges commence issuing their opinions from the side benches, where the least significant judges sit. The Gemara asks: From where are these matters derived? Rav Aḥa bar Pappa says: The verse states: “Neither shall you answer in a cause [al riv]” (Exodus 23:2), and the Sages interpret: Neither shall you answer after the Master [al rav], i.e., do not dispute the opinion of the greatest among the judges. Therefore, were the judges to commence issuing their opinions from the greatest of them, and he would say that the accused is liable, no judge would acquit him.
רבה בר בר חנה אמר רבי יוחנן מהכא (שמואל א כה, יג) ויאמר דוד לאנשיו חגרו איש [את] חרבו ויחגרו איש [את] חרבו ויחגור גם דוד את חרבו
Rabba bar bar Ḥana says that Rabbi Yoḥanan says: The source of this practice is from here: When David decided to punish Nabal the Carmelite, the verse states: “And David said to his men: Every man gird his sword. And every man girded his sword, and David also girded his sword” (I Samuel 25:13). That was a case of capital law, and David, the greatest among them, was last.
STRANGE Gemara! First we have a pasuk from Chumash to prove that מתחילין מן הצד. Then R' Yochanan cites a pasuk from the Navi???
