This site seems to confirm some of my points:
http://www.milknhoney.co.il/new/conversion.new.html
Judaism's Acceptance of Converts
Is it possible to reconcile the following Rabbinic sources?
The Only Reason G-d exiled the Jews among the nations was so that converts could be added (Pesachim 87b)
Continuous evil comes to those who accept converts (Yevamot 109b)
Converts are hard for Israel like a nasty soar. (Yevamot 109b)
'The Souls they made in Charan' These are the converts which Avraham and Sarah converted. This teaches us that whoever brings a gentile close and converts him it is as if he created that person (Bereshit Rabah 39)
The names of Gerim are dear to me like idolatrous wine poured on the alter. (Vayikra Rabah 1)
Even a gentile who converted and busies himself with Torah is considered like the Cohen Gadol. (Bamidbar Rabah 8)
Come and see how beloved converts are to G-d... (Ruth Rabah 2)
Although most of the laws of conversion to Judaism are straight forward, the reality of the matter can be as difficult as reconciling the above.
Yitro was Moshe Rabienu's Father in-law. According to many he was one of the first Gerey Tzedek - True Convert. However, the familial relation between him and Moshe was probably not the smoothest since Yitro was a Median idolatrous priest before his conversion.
And Moshe said to Chovav Ben Reuel the Midyanite, Moshe's Father In-Law, We are traveling to the place which G-d said he would give us, come with us and we will be good to you because G-d has spoken well of Israel. (Bamidbar 10-29)
The Midrash informs us that Moshe's father In-Law had many names. He was called Chovav because of his love for doing Mitzvot. His more popular name was Yitro. He was called Yitro because his suggestion added an extra paragraph to the Torah. The Pasuk and the Midrash demonstrate how accepting Judaism can be of converts. The Perasha containing the Ten Commandments is called Yitro.
However, Moshe Rabienu's relationship with his father in-law who is so beloved to the Jewish people did not necessarily start out in the most kosher way. Another Midrash which seems in opposition to the one above says that Yitro only agreed to give Moshe his daughter to marry if their first born was to be dedicated to Idolatry. Some say that this is the reason why Moshe did not circumcise his first born son until Moshe's life was endangered. (Torah Shelemah ?)
Building on this particular Midrash is Avot of Rabbi Natan and Baba Batra 109b which says that Yehonatan Ben Gershom Ben Menasheh who served as an Idolatrous priest (Shoftim 18-30) was really Moshe Rabienu's Grandson. Since the king Menasheh was terribly evil the Tanach made a play on words but "in reality" this Idol Worshipping Levite was really Moshe's Grandson.
These three Midrashic sources are not necessarily historic. However, they do accurately portray Jewish attitudes towards the assimilation of converts into the Jewish people.
They refer to Moshe Rabbienu who was the greatest man in Jewish history. They discuss his father In-Law who, as a convert, had a tremendous positive impact on the Torah's Judicial system and Judaism as a whole.
The Midrash is actually saying that Moshe in some way agreed to have his child dedicated to sick idolatrous practices. In saying that Moshe Rabbienu agreed our Rabbis of Blessed Memory touch on the negative side of relations between a Jew and his spouse's relatives. While trying to keep family relations Jews are usually flexible towards "that" part of the family.
The Statement in Avot of Rabbi Natan is saying that Yehonatan's great grandfather, Yitro, had an effect on him which "opened his mind" up to pagan customs. Is it possible that a convert as great and devout as Yitro could have a negative effect on his progeny?
What we have discussed until now refers to very devout converts to Judaism. However, not all converts to Judaism are whole hearted. Towards converts like Yitro we must be accepting. What should we do about those with ulterior motives? Throughout the ages accepting people with ulterior motives too seems to be an argument, although there does appear to be a lenient attitude.
In Bamidbar (11-4) we meet the Asafsuf. "The Asafsuf lusted for meat." These troublemakers riled up the whole nation to complain about the lack of meat. According to our Rabbis these people were trouble maker Gerim. They were the Erev Rav - a group of Egyptians who were impressed by the miraculous defeat of Egypt. They decided to follow the Jewish people. Their complaints about the Epicurean situation in the desert caused very many people to die.
Many converts and their offspring have done tremendous good for the Jewish people. Onklus the Convert comes to mind first. He translated the Torah into Aramaic so that the masses could understand it. Rabbi Akivah's grandparents were converts. Although he started out having great hatred for Rabbis he subsequently became one of the greatest leaders in Jewish History and was punished for this with a slow death at the hands of the Romans.
Our Rabbis of Blessed Memory have said that the prophet Ovadiah was an Edomite convert to Judaism. (Sanhedrin 39b) His prophesy predicts the downfall of Edom whose spiritual forebearers are the Christians.
However, Encyclopedia Judaica points out that according to Josephus during the time that the Bet Hamikdash was being destroyed many converts turned Jews into the Roman Authorities. I met several converts who when they converted were very honest about Judaism and Torah. However, after a while they got fed up with it and now hate most things which smell of Judaism.
The last two chapters of The Book of Ezra discusses the annals of the Jews who returned from the Persian exile. The last two chapters discuss how Ezra forced all of the returned exiles to divorce their gentile spouses and to disown their children. Ezra did not give the spouse's any option to convert.
Our Rabbis of Blessed Memory have said that no two prophets prophesy in the same way even if they are discussing the same issue. This seems true when we view some of Ezra's early contemporaries.
And many nations and great societies will come to look for the G-d of Hosts in Jerusalem and to seek G-d's favor. This is what the G-d of Hosts says, during those days 10 people of all of the foreign tongue will grab onto the corner of a Jew's garment and say let us come with you because we have heard that G-d is with you. (Zechariah 8-22,23)
From the East all the way to the West my name is great among the nations.... (Malachi 1-11)
The attitude discussed by these prophets seems to be welcoming of Gentiles who are seeking G-d and Torah. It seems difficult that these prophets spoke of universalism just a few years prior to many people being forced to divorce their loved ones. However, it must be noted that Ezra viewed the gentile spouses as ordinary idolaters. They continued to practice idolatry and were still filled with the filth of the gentiles. (Ezra 9-1 using the word "To'eva")
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The Rambam is very central to this discussion of accepting Converts. (Isurie Biah ch. 13)
14. Do not entertain the thought that Shimshon the Savior of Israel or Shlomo the King of Israel who was called "friend of G-d" married foreign women while they were still gentiles. Instead the real reason is as follows: The correct mitzvah is that when a potential convert, whether man or woman, comes to convert he needs to be checked after. Perhaps he wants to convert for money that he will get, or an authoritative position or out of some fear he would like to convert. If he is a man it should be checked whether he is converting in order to marry a Jew. And if she is a woman then it should be checked whether her eyes have been put on a Jewish boy. If no motive is found then they should be informed about the yoke of following the Torah and how difficult it is for the ignorant to follow the torah. This is done in order to convince them not to convert. If they accept this and are not turned off and we see that they are returning out of love [for G-d] as it says [in The Book of Ruth] "Because she was stubborn to go with her and she stopped trying to convenience her."
15. Therefore, The Bet Din did not accept any converts during the days of David and Shlomo. During the days of David because they might have returned out of fear. During the days of Shlomo because they might be converting to participate in the majesty, the goodness and greatness which Israel had in those day. Because whoever returns from being a gentile due to the vanities of the world is not part of those considered righteous converts. However, during the days of David and Shlomo there were still many converts in front of Hedyotot. (ordinary people) Then the Great Bet Din would be concerned and would not turn them away after they immersed. However we do not come close to these converts until we see their lot.
16. Since we see that Shlomo converted many women and married them. Also Shimshon converted them and married them. And we know that these [converts] returned out of ulterior motives. They were not converted through a Bet Din therefore the Tanach considers them gentiles and that they are still forbidden. Additionally, their end demonstrates what they really believed when they converted since they worshiped idols and built for themselves alters. the Tanach considers it that he (Shlomo) built them as it says "then Shlomo built an alter."
17. A convert who was not checked after or was not informed of the mitzvot and their associated punishments yet he circumcised and immersed in front of three ordinary people. He is still considered a convert. Even if it is subsequently clarified that he converted out of ulterior motives since he was circumcised and immersed he is no longer considered a gentile, however we still suspect him until his righteousness is proven. Even if he went back and worshipped idols he is considered as a rebellious Jew who performs idolatry whose marriage is considered a marriage. And it is a Mitzvah to return his lost articles since he immersed and is now part of Israel. Therefore Shimshon and Shlomo kept their wives even though their true [idolatrous] attitude was uncovered.
18. Therefore Our Rabbis of Blessed memory have said "converts are worse for Israel than soars" since most of them return for a reason and then they cause Israel to stray. It is difficult to get rid of them once they have immersed. Just look what happened in the desert with the Golden Calf and in the "tombs of lust" and so it is with most of the trials that the Asafsuf were a part of them.
Ch. 14 Hal 1. How do we accept converts? When someone who is a gentile comes to convert then he is checked after and no ulterior motive was found. They should say to him "what have you seen that caused you to come and convert? Do you not know that during these days Jews are lowly and pushed around, wanderers and trampled on? And that tribulations are brought on them? If he says "I know and it does not matter" he is immediately accepted.