Sanhedrin 19 – The King

A king may neither judge nor be judged. This applies to later kings, but kings of the Davidic line may judge and, therefore, be judged; as Resh Lakish explained, "First correct yourself, and then correct others"— only a person subject to correction may correct others.

But why may the other kings not judge or be judged? Because of an incident that once occurred. A slave of King Yannai killed a person, and Shimon ben Shetach called King Yannai to court - because "its owner had been warned by witnesses" that the king, the owner of the slave, had to be in court. Yannai came and sat down. Shimon ben Shetach told him to stand up, but the king said, "I will do as your colleagues will say." All the members of the Sanhedrin were looking into the ground. Shimon ben Shetach said, "You are men of deep thought! May the Master of thoughts exact retribution from you!" -" and they died. The Sages then decreed that a king may neither judge nor be judged.

Art: St Louis, King of France by El Greco