Sanhedrin 2:1-2

Sanhedrin 2:1

The Kohein Gadol (High Priest) may serve as a judge and may be tried in court; he may testify as a witness and others may testify against him; he may perform chalitzah (the shoe-removal ceremony) and others may perform chalitzah or yibum (levirate marriage) with his widow but the Kohein Gadol does not himself perform yibum because he is not permitted to marry a widow. If one of his parents died, he may not accompany the procession. Rather, when the procession has turned to another street, then he may enter the street they just vacated; he may not enter a street until they have left it. Rabbi Meir says that the Kohein Gadol follows the procession until they reach the city’s entrance, but Rabbi Yehuda says that he doesn’t even leave the Temple, based on Leviticus 21:12, “Nor may he leave the Sanctuary.” When the Kohein Gadol consoles mourners, the normal way of people is for one to pass by after the next; the deputy Kohein Gadol places himself between the Kohein Gadol and the people. When the Kohein Gadol is consoled by others, they say to him, “May we be your atonement” and he replies, “May you be blessed from Heaven.” When the people bring him the meal of consolation, they sit on the ground and he sits on a stool.

Sanhedrin 2:2

The king may not serve as a judge nor may he be tried in court; he may not testify as a witness and others may not testify against him; he does not perform chalitzah and it is not performed for his widow; he does not perform yibum and it is not performed for his widow. Rabbi Yehuda says that if the king chooses to optionally perform chalitzah or yibum, he is remembered with favor for it; the Sages replied that we do not permit him to forgo his honor in this way. No one may marry the king’s widow. Rabbi Yehuda said that a king may marry the widow of another king since we see that David married Saul’s widow, as per II Samuel 12:8, “I gave you your master's house and your master’s wives into your embrace.”