Let's suppose someone wants from all his heart to convert, has no ways to travel for an official conversion and decides to convert himself and to follow all halachot and mitsvot of the Torah.

I have seen some rabbanim saying that after some years he will be considered to be a Jew, that by halacha directly!

What are the sources?

PS. For the sake of clarity, I am asking about Orthodox practice


3 Answers 3


The Rambam in his Mishne Torah, Hilchot Issurei Biah chapter 14 (see also 13:4) outlines the procedure of a formal conversion. Some of the key steps are

  • inspecting the non-Jew for ulterior motives
  • informing him/her of the fundamentals of the Jewish faith and some of the easy/harder commandments as well as their reward and punishment
  • checking he understands "what he is getting into" (e.g., persecution of the Jews, acceptance of the commandments)
  • for a male, circumcision
  • having a court (three judges) oversee the immersion in a ritual bath (mikve)

As such, it is not possible according to halacha to convert oneself. I have never ever heard of any Orthdox rabbi approve a self-conversion even after a few years.

PS. Also note it is nearly impossible to observe halacha properly if not learning from other Jews, one cannot learn only from books


The source is a Gemara with Rabbi Yehoshua Ben Levi in Yebamot 45b. Someone was taunted, people called him Aramaic. RYBL was astonished by this gossip, "he doesn't go to mikve (a mikve kosher for nidda) when he's Baal Keri.

So the case seems to be this: A man was living in Jewish community and behaved as last people of this community. Assuming that he comes from a non Jewish family and nobody remembers his conversion. We assume that he is a convert equivalent because he's practically mekabel ol mitsvot and did tevila. But we need an explicit proof in poskim that to be known by a lot of people as shomer mitsvot is sufficient to be equivalent of kabalat ol mitsvot before 3 dayanim ediotot. Maybe that is not the case. Maybe RYBL did know that he already made a kabalat ol mitsvot with 3 dayanim.

ההוא דהוו קרו ליה בר ארמאה אמר ריב"ל ומי לא טבל לקריו. ‏

In Shulchan Aruch YD 268.3 you can see the halacha, approximately the restriction from the Rif is that this din is valuable bediavad only to avoid to see his children from a Jewish woman as pegumim as sons of a non-Jewish father.

  • The question seemed to imply that the person did not have any Jewish neighbors. Commented Jan 20, 2019 at 11:55

A good Q. and I remember answering it elsewhere, but others didn't like my answer so much.

We have a "loophole" in Halacha that's called Chazakah (a presumption) and it works in many many areas of expertise in cases we don't have witnesses or a trusted document. For example, clothes or watches that you wear are presumably yours, if you work in a field for three consecutive years it's presumably yours, if you and your girlfriend come to a new community and cohabit with her you become presumably married, if a woman comes from far away and holds a child she continues to fosters for years he becomes presumably her son.

So if you're not a Jew, but come to a new community that can't check your background (very difficult nowadays) and keep the Torah and Mitzvos you become presumably a Jew by a Chazakah. Of course you'll be a sort of a "second-grade" Jew, a Jew without ancestry, but still a lawfull Jew.

It is very easy to visualize: think about driving by the countryside at late night and hitting a man. He's hurt and unconscious but nothing serious. He looks like a full-fledged Chassid - black coat, Shtreiml, white socks etc. When he awakens he remembers nothing and has no IDs. You post his picture on every social network but nobody recognizes him. He knows all the Halachos and keeps them piously. What would you do? Would you accept him into your community or suspect he's a masquerading gentile? Well, if he walks like a duck and quacks like a duck ...

The second part about G-ds acceptance, I think, is even easier, because it is commonly accepted that one who truly wants to be a Jew and keep the Torah already has a Jewish soul (why would he otherwise). So the conversion is always only a formal communal acceptance, just as a marriage.

THe sources for this statement are:

  1. Rambam's ruling at the end of Melachim (): "משפחה אשר נטמעה נטמעה". Meaning that IF somehow a Mamzer was eventually accepted as a regular Jew, his descendant will always keep the status of regular Jews. So I learn Kal Vachomer, because a Mamzer is a strict prohibition.

  2. Before Matan Torah there were no courts and everyone (incl our forefathers) just accepted Judaism on their own.

To your question - there's no other way to be accepted as a Jew if your gentile past is known to all.

  • Do you have a source that chazaka applies to someone who has lived as a Jew without being one? That is the crux of your argument
    – mbloch
    Commented Jan 19, 2019 at 18:11
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    Also aren't you confusing the fact that a community might (wrongly) think you are a Jew with the actual status in the eyes of Hashem?
    – mbloch
    Commented Jan 19, 2019 at 18:11
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    @AlBerko maybe a gentile wants to convert to marry a Jew? Now we can discuss all night long if that means (s)he has a Jewish soul or not. No one knows. Will Hashem accept him/her without conversion? Also note that your second source from before matan Torah is irrelevant after matan Torah. Nothing personal, I am just afraid that what you write is simply wrong
    – mbloch
    Commented Jan 19, 2019 at 18:45
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    @mbloch we represent two different approaches (maybe Letvak vs Chusid). You look at the Kankan and I look into it. My answer just shows a loophole, implying that the original Halacha you mentioned stays in place. As I provided multiple examples when we do accept Chazokos even for Arayos.
    – Al Berko
    Commented Jan 19, 2019 at 18:52
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    @mbloch judaism.stackexchange.com/questions/98568/… Please answer there.
    – Al Berko
    Commented Jan 19, 2019 at 19:03

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