הלכה על סנהדרין 3:7

Chazal do not require a dayan (rabbinic judge) to explain the reasons for his decisions. The Mishnah (Sanhedrin 3:7) presents the procedure for a beit din issuing its decision: “The most prominent of the judges announces, ‘Mr. so-and-so, you have prevailed, and Mr. so-and–so, you are liable.’” No mention is made of a requirement for the beit din to offer explanations for its decision. In fact, the Shulchan Aruch (C.M. 19:2) states that when one of the litigants requests a written decision, the beit din writes, “So-and-so came with so-and-so his fellow litigant before beit din, and it emerged from their words that so-and-so was victorious and so-and-so was liable.” No mention is made of a requirement to explain the decision.