Once the [judges] reached a verdict they would bring in [the defendant]. The senior judge would say, “Mr. Doe, you are innocent,” or, “Mr. Doe, you are guilty.” What is the source [for the practice] that when one of the judges goes out [of the court] he must not say, “I exonerated [you] but my colleagues found you guilty; what can I do since they are in the majority?” Regarding this it says (Lev. 19:16), “Do not go talebearing among your people,” and it says (Prov. 11:13), “the talebearer reveals a secret.”
Rabbinic law does not use peer juries, but rather relies on courts of sages. The smallest court consists of three judges. Ancient Jewish cities maintained courts of twenty-three judges. In Jerusalem, the great Sanhedrin of seventy-one judges ruled on matters of national significance. All courts had an odd number of judges to prevent a deadlock. Although unanimous opinions were not required (indeed a unanimous opinion to execute a criminal was considered suspect), our Mishnah indicates that the internal deliberations of the court were considered secret.