Horayot, Chapter Two, Mishnah Five
The main topic of our mishnah is the king (a ruler, see below 3:3) who accidentally transgresses. In Leviticus 4:22-23, we read, In case it is a chieftain who incurs guilt by doing unwittingly any of the things which by the commandment of the Lord his God ought not to be done, and he realizes his guiltor the sin of which he is guilty is brought to his knowledgehe shall bring as his offering a male goat without blemish. The question asked by our mishnah is for what sins does the king bring this type of sacrifice.
I) [The court] is not obligated [to bring an offering] for [an errant ruling relating to] the hearing of the voice [of adjuration]; for an oath made by an expression, or for impurity relating to the Temple and its holy things.
II) And the ruler is similarly [exempt]; these are the words of Rabbi Yose Hagalili.
A) Rabbi Akiva says; the ruler is liable in the case of all these except that of hearing of the voice [of adjuration], because the king may neither judge nor be judged, neither may he testify nor may others testify against him.
Section one: This section basically states what we have already learned above. A court that issues an errant ruling is liable to bring a bull as a sin offering only if the transgression was one which if done unwittingly can be atoned for with a sin offering. The three transgressions mentioned in this mishnah are atoned for by sliding scale sacrifices (the rich bring a goat, the middle class bring bird and the poor bring grain, see Leviticus 5 and tractate Shevuot). The first transgression is the taking of a false oath that he does not know any testimony, called in our mishnah the hearing of the voice of adjuration. It is called this because usually someone adjures someone else to take this oath (I adjure you that you do not know any testimony concerning me). The second transgression is in regard to an oath of expression. This is when a person swears that he will or will not do something. The third transgression is either entering the Temple impure, or eating holy food while impure. If the court makes an errant ruling with regard to any of these laws, the court is not liable to bring a sin offering.
Section two: According to Rabbi Yose Hagalili, the same is true if the ruler, or king, accidentally transgressed one of these commandments. The reason is that a sliding scale sacrifice is not applicable to a king, for a king never becomes poor. Leviticus 5:7, 11 state, But if his means do not suffice. Since this can never be true of a king, who always has financial means, Rabbi Yose Hagalili concludes that the entire law and sacrifice is not applicable to the king. In other words, the king is not simply in the category of a rich person, because rich people can become poor, while kings do not.
Rabbi Akiva disagrees and says that the king can be liable to bring a sliding scale sacrifice for all of these sins, with the exception of oaths of adjuration. Since the king cannot judge or be judged, testify or be testified against, he is considered outside of the framework of the regular legal system. If someone adjures him that he doesnt know testimony and he swears that he does not know testimony, but in reality he does, he is not liable for a false oath. This is because even if he had admitted that he knows testimony, he cannot testify in a court of law (see Sanhedrin 2:2).