Horayot, Chapter One, Mishnah Four
This mishnah really contains two totally separate mishnayoth. We will therefore explain each separately.
Mishnah Four, part one
If the court ruled and one of them knew that they had erred and said to the others, You are making a mistake,
or if the mufla of the court was not there,
or if one of them was a proselyte or a mamzer or a nathin or an elder who did not have children, they are exempt, for it says here (Lev 4:13) congregation and it says later on (Num 35:24) congregation; just as the congregation further on must be fit to issue rulings, so too the congregation mentioned here must be fit to issue rulings
This mishnah teaches three principles. First of all, if even one judge on the court knew that the court had erred in its ruling and told the rest of the court so, and yet his advice was overrode, the court is not liable to bring an offering if people transgress by obeying their ruling. For the special law of the erring court to be in effect, the entire court must err.
If the mufla was absent when the errant decision was made, the court is not liable. The mufla was evidently the person who sat on the court and had many, many halakhot memorized. He was like a human archive who could recite orally from the tradition. His absence would have impeded the courts ability to make the correct decision, and therefore they are not liable.
The third rule is that all of the members of the court must be fit to issue rulings. Our mishnah lists several categories of people who are not fit for this type of court. Converts, netinim (Temple slaves) and mamzerim (children born of illicit marriages) cannot act as judges in capital cases (see Sanhedrin 4:2). The innovation of our mishnah is that an elder who does not have children can also not act as a judge. This is because we are concerned that he will not have pity on others when it comes to adjudicating capital cases. In other words having children makes a person more compassionate. Personally, I can say that when my first child was born I began to look at other human beings differently; everybody is somebodys child. Having children can certainly increase a persons sense of the suffering of others. [I dont mean to say that one who doesnt have children is necessarily not sympathetic to others suffering. When the mishnah sets qualities for judges it bases itself on the most likely norm and not on the range of possibilities for human characteristics].
This third rule is learned through a midrashic technique called a gezerah shavah, which is a linguistic comparison. The word congregation (edah) is mentioned here in Lev 4 and in Num 35, which discusses capital cases brought before a court. From those verses the rabbis learn that capital cases are tried before a court of 23 (see Sanhedrin 1:6). Just as in capital cases, if there are not 23 qualified judges, the judgment is invalid, so too here, in order for the law that requires an offering for an unwitting errant ruling to be applicable, there must be only qualified judges.
Mishnah Four, part two
1) If the court issued a decision unwittingly and all the people acted unwittingly, they bring a bull.
2) [If the court ruled wrong] intentionally and [the people] acted unwillingly, they bring a lamb or a goat.
3) [If the court ruled] unwittingly and [the people] acted willingly accordingly, they are exempt.
Section one: This first section is the classic case in which the court must bring the bull as a sin-offering (mentioned in Lev 4:14).
Section two: In this case the court intentionally made the wrong ruling. They therefore cannot bring the bull as a sin-offering because intentional sinners are not allowed to bring offerings to atone for their sins. Sin-offerings are an opportunity for atonement, and not a punishment. Only one who sinned accidentally is given this opportunity to atone through sacrifice. [Intentional sinners can possibly achieve atonement in other ways]. Since the court cannot bring an offering, the people are considered as individual unwitting sinners, and they bring the typical sacrifice for a person in such a category: a lamb or goat (Lev 4:28, 32).
Section three: If the court unwittingly ruled in error but the congregation knowingly sinned, the court does not bring the bull offering because the congregation did not act based on the courts ruling. The congregation knew that the act was wrong, even though the court said it was permitted. Since they did not act upon the courts ruling, the court is not held responsible for their transgressions. The congregation cannot bring an offering since they transgressed intentionally. As we learned in the previous section, intentional sinners cannot achieve atonement through sacrifice.