Rabbi said - Is it not enough for Ba'alei Teshuva that they are accepted [as penitents], that they are even called Rabbi?
Babylonian Talmud, Avodah Zarah 17a
This must be one of the most ironic sentences in the Talmud, which is a pretty ironic work to begin with. But there are certain people who tend to miss the irony in life. And they take this, too, literally. Clearly, they apparently say, it is better not to accept penitents. Not that they should not do teshuvah. But even when they do, they will not be accepted into society.
The Bible devotes a great effort to emphasizing the importance of not mistreating proselytes, the strangers in your midst. While there are obvious differences between proselytes and the newly-religious, the similarities are very strong.
It would seem that Jewish society has long been lax in its performance of this commandment. In an article I hope will appear soon, an important young scholar charts changes in the attitude of Ashkenazic society towards converts. During the First Crusade, a convert who was about to murdered, along with the rest of the Jewish community in which he lived and which had refused to be baptised, shouted out to his compatriots: "You, who always doubted my sincerity - watch as I am killed for my adopted faith!"
Speaking of medieval converts to Judaism - a new collection of studies has just been published on Ovadiah of Oppido, a convert whose existence was revealed by the Genizah. He was born Johannes, a Norman in southern Italy. He converted to Judaism in 1102 and moved to Aleppo. He is the first person known to have used musical notations in Hebrew. He also wrote an autobiography, which was published in the 1970s and '80s. Mauro Perani edited a volume titled Giovanni-Ovadiah da Oppido, proselito, viaggiatore e musicista dell'eta normanna, Firenze 2005. Besides studies by a wide range of scholars (including Robert Bonfil, Norman Golb, Cyril Aslanov, Benjamin Zvi Kedar, Elinoar Barkat and Andre Hajdu), the book contains facsimiles of all the pages identified as having been written by Ovadiah.
As the example of Ovadiah the Norman demonstrates, converts and other newcomers contribute a great deal to the vitality of the society which they join. If there is any downside to such a transition, it is the price these people pay, both in terms of the group they are leaving which feels betrayed, and the group they are joining which - at the best of times - is more comfortable with oldtimers. To ostracise them is not only to sin, but also to lose out on what they have to offer. And to accuse them of being a bad influence on the "pure-bloods" is both wicked and stupid.