What does a Jew "convert" to? He believes in his own Moshiakh.
Well I think there would be a conversion later on in the case of the more highly divergent forms of Judaism that exist today, such as Chasidic Judaism, or vanillia orthodox Rabinnical Judaism, or Reform Judaism, with their Rabinnical system, the Talmud (or rather technically two Talmuds, but the one that is most important is the Babylonian Talmud), and since the Talmuds and the Mishnah are not accessible to laity, you have the Torah as interpreted by the Rabbis based on the Mishnaic recension of the oral traditions of the Pharisees distilled into the Sulchan Aruch, which addresses the needs of the Sephardic community and has an Ashkenazi gloss which is almost invariably prrinted with it, making it a fascinating and enjoyablle book, and then of course uniting all of these groups even Reform, although I am not sure about Reconstructionist Judaism, as I don’t quite understand their belief system, you have a large number of Jews who are into the mystical system of Kaballah, which imparts esoteric significance even to seemingly banal portions of the Talmud that address the practicalities that any legal system must address.
And then Karaite Judaism, excluding the Khazars of Ukraine*, also seem to have moved away from Christianity to quite an extent; some might argue they invented Sola Scriptura, although really, their approach to reading the Hebrew Bible is more like Prima Scriptura, in that it depends heavily on a system of methodical reasoning known as the Kalaam (similiar systems have also been used by Islamic philosophers). And there is an accepted prevalent interpretation of the Hebrew Bible by the Karaites, which is obviously a tradition, and in this traditional Karaite orthodoxy, on the basis of their analysis of the text using the Kalaam, among other unusual conclusions, they have come to believe that the devil does not exist, and that the serpent in the Garden of Eden was merely a very cunning and intelligent snake. I find this bizarre.
This group unfortunately suffers some degree of discrimination from the Chief Rabbinate of Israel (yes, I understand that Karaite standards of Kashrut are such that a Kosher butchers operated by Karaites would perhaps not be Kosher for Rabinnical purposes, but denying them the phrase Kosher altogether seems excessive, it seems it would be more reasonable to let them identify as “Karaite Kosher”, but the secular government does treat Karaites and the Beta Israel (Jews from Ethiopia and their descendants, whose synagogues perform animal sacrifices and follow a liturgy and use vestments that closely resemble the Ethiopian Tewahedo Orthodox Church, albeit with the animal sacrifices taking the place of the Eucharist; the Beta Israel are the descendants of what at one time was the predominant religion in Ethiopia and Eritrea, as I’m sure my friends
@Yeshua HaDerekh and
@dzheremi are aware, but sadly most Christians are unaware of the Ethiopian church, despite the enormous influence it has had, for example, the little-known but very important influence its mere existence had on Martin Luther when he was contemplating what to do in response to doctrinal errors in the Roman church; also, interestingly, the Ethiopian Tewahedo Orthodox Church has probably the highest ratio of Christians descended from Jews.
The other churches with large numbers of members of Jewish descent include the Syriac Orthodox and Antiochian Orthodox churches (many members have recognizably Jewish components in their names, such as the current Syriac Orthodox Archbishop of the Western United States, Mor Clemis Eugene Kaplan, or the late Syriac Orthodox Patriarch Ignatius Zakka Iwas I, memory eternal (or anyone named Zakka, which is a Syriac form of the name rendered in Koine Greek as Zacchaeus), and the Aramaic speaking community in Maaloula in Syria, whose nuns were kept hostage by Al Nusra, the local Al Qaeda affiliate, and whose churches were desecrated; fortunately the community survived, likewise the Greek Orthodox Patriarchate of Jerusalem has many members in Israel and the Palestinian territories who speak Arabic, Aramaic and/or Hebrew, who like most Arabic speaking Christians in the Holy Land are at least partially descended from Jewish Christians. Then you have the Assyrian Church of the East, which has a large and obvious Hebrew influence, indeed, their main liturgy, which is also believed to be one of the three oldest in continual use, the Divine Liturgy of The Holy Apostles Addai and Mari, is structured in the manner of a Jewish table blessing, as noted by Dom Gregory Dix and others. And at one time, the Church of the East extended throughout Asia, to the island of Socotra off the south coast of Yemen, and to Mongolia, China and Tibet, with a major hub in the lost city of Merv, near the modern day city of Mary in Turkmenistan (which is home to a Russian Orthodox Church to this day, which pleases me; I would love to go there, and visit the ruins of Merv with the local Russian Orthodox community, but alas getting an invitation and a visa to Turkmenistan is notoriously difficult).
However, the Muslim warlord Tamerlane and his sons launched a genocide which killed off the Church of the East everywhere except its two major historic strongholds, in modern day Iraq, Iran and eastern Syria (an area which partially overlaps the eastern province of the Syriac Orthodox Church), and in India, and among both populations there are substantial Jewish converts, for the Church of the East was historically always headquarted in Seleucia-Cstesiphon, and then when that city became uninhabitable due to a shifting of the Tigris, moved into its successor, Baghdad (which is much closer to ancient Bablyon). It was in Seleucia-Cstesiphon that the great Jewish sages Rav Ashi and Ravina II completed the monumental Bablyonian Talmud, and they spoke a dialect of Aramaic which is not greatly different from the vernacular East Syriac spoken by the Assyrians of the time, including the Catholicos-Patriarch, or presiding bishop, and the other bishops and priests and monks who worked in the capital. The Eastern province of the Syriac Orthodox Church has always been run by a bishop originally titled the Catholicos, but after the schism between that church and the Church of the East, his title was changed to the Maphruno (commonly Anglicized as the Maphrian), and one of the most beloved Maphrians was Mar Gregorios bar Hebraeus, a 12th century Jew who embraced Syriac Orthodox Christianity and rose to become the Maphrian, and who also was much loved by the Assyrians of the Church of the East, so much so that when he died in an Assyrian town in the Nineveh Plains while returning from the city of Tikrit, which has many Syriac Orthodox Christians, to his monastery, the Monastery of St. Matthew, which still overlooks the city of Mosul, having miraculously survived the occupation of that city by ISIS, the Catholicos-Patriarch of the Church of the East arranged his funeral, and over four thousand Assyrians attended.
Thus, because of these differences, and also those involving the Beta Israel, and for that matter we might as well include the Samaritans, who more likely than not are descended from the tribes of Ephrem, Manessah and, based on genetic analysis, the Levites and Kohanim, it does seem that given how Samaritanism had diverged from Judaism, and given how Judaism has diverged, in all three of its major forms (Rabinnical, Karaite and Ethiopian), that in the modern day, when a Jew becomes an Orthodox Christian, they are converting. Now it should be clear from what I have written that I love Jews, I find Judaica fascinating, I see the Jewish and Samaritan liturgical traditions in particular as being extremely valuable, because it is clear that our Christian liturgy was heavily influenced by them, for example, the three main daily prayers of the Jews became the basis for our three main prayers of Matins, Vespers and Compline, although we supplemented these in most churches with additional prayers, and likewise the animal sacrifices of the Hebrew religion, which at present are engaged in only by the few remaining Beta Israel of Ethiopia and their large diaspora in Israel, prefigured typologically the one all sufficient and voluntary sacrifice of Christ our True God on the Cross, through which humanity was remade in the image of God, before He rested on the seventh day, just as He had in the beginning, and then rose on the eighth day, just as we will, on the mystical Eighth Day of Creation, be raised incorruptible, to face the dread judgement seat of Christ, and those of us spared by the Incarnate Logos will then live with God, the Father, Son and Holy Ghost in the World to Come, whereas those who despise God will be spared the torture of being in his immediate presence by being sent to the outer darkness, where they will punish themselves through infinite regret over the joys they chose, and continue to choose, to actively reject, for as CS Lewis observed, the gates of Hell are locked on the inside.
The reason why this is a conversion for Jews is because Jews do not worship the Trinity, but developed, in opposition to Christianity and to the ancient Hebrew religion, which clearly had proto-Trinitarian concepts such as the idea of the Logos and the Holy Spirit, even if these were not at all well understood, particularly by the time of Christ, as well as proto-Eucharistic aspects to its liturgy, in the form of the drink offerings and shewbread in the Temple, among other things, a strongly Unitarian, monarchistic approach to God. The Rabinnical Jews then went beyond that, with Kaballah, and embraced a mystical system in which God divides into ten Sephirots before recombining, and each of these has distinctive attributes, and there is a complex mystical, emanationist system surrounding them, and some Jews believe that Kaballah has been used for such interesting purposes as animating a giant clay man, the Gollem, to defend the Jews of Prague from a pogrom.
Now this all being said, I absolutely detest anti-Semitism and I bitterly regret the way Christians have treated Jews over the preceding centuries, with some exceptions. Indeed, even on those occasions where we have been mistreated by Jews, we have no business persecuting them, for Christ commanded us to bless those who persecute us. Thus, while I do support efforts to convert the Jews to Christianity, including low-key efforts conducted by the Orthodox (who will receive Jewish converts and work on an approach that is based on attracting Jews and other potential converts through the beauty of our liturgy, and this approach works, and also keeps us safe, particularly in the Middle East where direct proselytism of Muslims, for example, is impossible, so attracting Muslims in the same way is the only way they can be evangelized without endangering the Christian communities, who are always, it seems, one accidental offense or intentional act of malice on the part of a zealous Mufti away from being exterminated; the Jews on the other hand do not react violently to proselytism, and also share the same essential morality of Christians thanks to the Torah and the Noachide Laws (which were reflected in the Council of Jerusalem in Acts 15) so I also support an Anglican mission in the Holy Land which does engage in active proselytism.
*The Khazars from what I have read largely renounced Judaism and embraced a reconstructed version of their ancient religion, while retaining some ecclesiological frameworks from Judaism (similiar to how Tibetan Buddhism adopted the hierarchical structure of the Church of the East and retained it even after all of the Christians in Tibet were killed by the genocide initiated by Tamerlane, possibly with Buddhist indifference or active assistance, as there have been many documented instances of Buddhist persecutions of Christians, particularly of Catholic missionaries in Japan and China),