Question
How many rabbis are required to constitute a Beth Din (Jewish Court) for orthodox Judaism? Who determines, and how, whether a person is qualified to sit as a dayan on a Beth Din?
Answer
Generally speaking, three rabbis constitute a beth din. Generally, each party (the disputants) selects one rabbi and the two selected rabbis, in turn, decide on a third. [Although it is not abnormal for one rabbi, that both parties agree to, to arbitrate a dispute or monetary matter on his own.]
In order to qualify to sit as a judge on a beth din, one must complete years’ worth of intensive study of Jewish (Torah) monetary law and practices and then receive some sort of ordination from a Rabbi (himself ordained as well).
Rabbi Moshe Rosenstein