What is the function of a beis din in regards to a non-Jew becoming a Jew

Question

In order for a male non-Jew to become Jewish he needs to do three things which all must be performed in front of a Beis Din (panel of 3 judges.) Those are that he must have a bris milah, accept upon himself the Mitzvos and go to the mikveh. For a woman it's the same thing (less the bris milah of course.)

However what would be the din of a person that (let's say in a woman's case where there is no bris involved) accepted upon herself the mitzvas and then went into a kosher mikveh without a Beis Din present. Or perhaps there were only 1 or 2 Jewish people present. Or perhaps there were three present but not all were "orthodox" Jews.

It seems that while one should definitely have a Beis Din lichatchila, would would be the din b'dieved (post facto) if they didn't have an "official" beis din?

Answer 1

It is a Biblical injunction that there must be 3 people involved at some point in conversion as in a monetary court decision - see the top of Kiddushin 62b, for example: גר צריך שלשה מאי טעמא משפט כתיב ביה כדין.

Where in the process the 3 are necessary is more debatable. Tosefos to Kiddushin 62b writes that the 3 are necessary for acceptance of mitzvos, but not for immersion into the mikvah. Rambam Issurei Bi'ah 13:7 writes that 2 is not enough, even after the fact, for immersion.

Shulchan Aruch Y.D. 268:3 writes that 3 who are eligible to sit in judgement should ideally be present for all aspects (informing the mitzvos, acceptance thereof, and immersion[and circumcision]), but as long as 3 were present for the acceptance of mitzvos, even if there were only 2 present for the immersion (and circumcision) it would be OK (as per Tosefos). He then brings the dissenting opinion of the Rambam.

There is no need for an "official" beis din - just 3 people fit to sit on a beis din. The Rema in his glosses to Y.D. 268:2 adds that the 3 people should be Torah scholars.

Answer 2

Geirut is just one of many matters that must be adjudicated by a beit din. The minimum size of a beit din is three per halacha. (Sometimes it's larger, as elaborated in the mishna in Sanhedrin.) So without a beit din you have only an intention to convert, but not a recognized conversion. For more on the requirement of a beit din for conversion, see Becoming a Jew by Rabbi Maurice Lamm, excerpted here.

See also the discussion in the g'mara on Yevamot 47, where the trustworthiness of a ger with no witnesses is discussed. The rabbis conclude that witnesses are required; the beit din serves that function. (This is one reason that the beit din must consist of Shabbat-observant adult men.)

But, you might ask, what about Ruth, who converted in her conversation with Naomi? There are several opinions that she in fact converted earlier, or converted conditionally earlier and later confirmed. While we take from that conversation the custom of trying to dissuade a convert, we can't conclude from that that Ruth converted without a beit din.