Mishnah — Seder Nezikin, Tractate SanhedrinChapter 3…
“ It is an explanation of what disqualifies a person from serving as a witness or judge, based on their relationship to the litigants, rather than by their profession. Obviously, these people could serve as a witness or judge in another case, unlike the people described in the previous mishnah, who are illegitimate for any monetary case. ”
