The Beit Din (Rabbinic Court)
Final authority for conversion rests with the three-person beit din, which rules on a candidate's sincerity, knowledge, and potential for success as a Jew.
Excerpted with permission from Becoming a Jew (Jonathan David Publishers, Inc.).
Formal conversion to Judaism requires authorization by a Jewish court. This three-man beit din represents, in a manner of speaking, the whole Jewish people into which the convert seeks entrance. It has the power to authorize or deny the application to join its ranks.
Traditional Requirements for a Beit Din
The beit din [for a conversion] consists of three individuals, as it does in regard to cases other than conversion--at least one of whom must be an ordained rabbi expert in the subject of conversion. Some sages of the Talmud derive the requirement of a beit din from the biblical verse, "You shall have one manner of law, as well for the proselyte as for the home-born. One law shall there be for you and for the convert" (Leviticus 24:22). Others derive it from the verse, " And thou shalt judge righteously between man and his brothers and the convert…" (Deuteronomy 1:16).
This much is certain: There is to be no difference in the legal process as regards Jews and converted gentiles. As the rules of justice for cases between one Jew and another require a court of three presiding in session during daylight, so too, in all cases between converts and Jews. In matters of the conversion protocol as well, the process is identical--neither more nor less strict--so the halakhah requires three Jews, knowledgeable about the conversion procedure, to oversee the protocol, and it must be held only during daytime.
A problem arose over the requirement of ordained rabbis. While there are many rabbis today who are traditionally ordained, the historic chain of ordination technically linking present-day rabbis with Moses is considered to have been broken. But if there are technically no ordained rabbis today whose lineage stretches back from student to teacher to Moses, what will happen to the conversion process which requires it? Shall Judaism therefore no longer accept converts because the law cannot be fulfilled as completely as the sages determined it should be?
The Tosafists, medieval French scholars, therefore, ruled that the biblical insistence that conversion be a "statute forever throughout your generations" (Numbers 15:15) takes precedence. The requirement of historic ordination had to yield to the biblical mandate on conversion that it be available "for your generations"--able to be practiced for the entire duration of Jewish history. Conversion was not a policy emanating from one period in history or one country--it is part of the warp and woof of the Jewish religion. The rabbis of the court were to be considered as "messengers" of the early rabbis who were ordained in the chain still tied to Moses.