There is significant debate among various Messianic Jewish organizations over whether or not it is appropriate to provide a formal process for non-Jewish Messianic Believers to “convert” to “Messianic Judaism.” Rabbinical Judaism embraces a formal process — based upon the Talmud, not upon Scripture — whereby a Gentile may “convert” to Judaism. The process is described in a WikiPedia article as follows:

The Amora'im who produced the Talmud set out three requirements for a gerut to Judaism (Keritot 8b), which must be witnessed and affirmed by a beth din:

• Circumcision (Brit milah or hatafat dam brit) for men

• Immersion (tevilah) in a ritual bath (mikveh) for both men and women

• Offering a certain sacrifice (korban) in the Temple (the Beit Hamikdash) - this requirement is deferred while the Temple does not exist until such time as it may be rebuilt.

The consensus of halakhic authorities also requires a convert to understand and accept the duties of the halakha, classical Jewish religious law. This is not stated explicitly in the Talmud, but was inferred by subsequent commentators.

After confirming that all these requirements have been met, the beth din issues a “Certificate of gerut” (Shtar Giur), certifying that the person is now a Jew.

As a practical matter, the requirements may be restated like this:

The candidate for “conversion” must:

1. apply for gerut and be denied twice

2. renounce his or her current religion, and explain the difference between the current religion and Judaism

3. affirm his or her desire to become a part of the Jewish religion (generally accomplished by “enrolling”—either formally or informally—in a course of halakhic study under a supervising rabbi)

4. adopt a Jewish name (a shem kodesh)

5. (for men) undergo brit milah (ritual circumcision) by a mohel; if already “medically” circumcised, there must be a fresh drawing of blood (hatafat dam brit) by a mohel (the Reform and Reconstructionist movements generally do not require a circumcision as part of the conversion process)

6. undergo tevilah (ritual immersion) in a mikvah (a pool of “living” water)

7. make a sacrifice at the Temple (since no Temple is available, the candidate may make a charitable donation as a substitute for the sacrifice) 

A review of the definitions of the words “convert” and “conversion” is appropriate here.

convert, n. a person who has been converted to another religious or political belief

convert, v. 1. change religious beliefs, or adopt a religious belief; 2. cause to adopt a new or different faith

conversion, n. 1. a spiritual enlightenment causing a person to lead a new life; 2. the act of changing from one use or function or purpose to another; 3. a change of religion; 4. an event that results in a transformation

It should be noted that there is absolutely no formal process for “conversion” given in the Scriptures, the Jerusalem Council (Acts 15) specifically ruled that no “conversion” process is appropriate, and Rav Sha'ul specifically taught against a formal “conversion.” (It must be remembered that Rav Sha'ul used the term “circumcision” as a technical term for “Jewish” and “uncircumcision” as a technical term for “non-Jewish,” and not necessarily as a reference to the brit milah itself.)

Only let each person live the life the Lord has assigned him and live it in the condition he was in when God called him. This is the rule I lay down in all the congregations. Was someone already circumcised when he was called? Then he should not try to remove the marks of his circumcision. Was someone uncircumcised when he was called? He shouldn't undergo b'rit-milah. Being circumcised means nothing, and being uncircumcised means nothing; what does mean something is keeping God's commandments. Each person should remain in the condition he was in when he was called. Were you a slave when you were called? Well, don't let it bother you; although if you can gain your freedom, take advantage of the opportunity. For a person who was a slave when he was called is the Lord's freedman; likewise, someone who was a free man when he was called is a slave of the Messiah. You were bought at a price, so do not become slaves of other human beings. Brothers, let each one remain with God in the condition in which he was called.  (1 Corinthians 7:17-24, CJB; emphasis added)

Rav Sha'ul also clearly taught that the non-Jewish individuals who have come to saving faith in Yeshua HaMashiach are already “fellow-citizens with God’s people and members of God’s family” (emphasis added).

1 You used to be dead because of your sins and acts of disobedience. 2 You walked in the ways of the 'olam hazeh and obeyed the Ruler of the Powers of the Air, who is still at work among the disobedient. … 11 Therefore, remember your former state: you Gentiles by birth - called the Uncircumcised by those who, merely because of an operation on their flesh, are called the Circumcised - 12 at that time had no Messiah. You were estranged from the national life of Isra'el. You were foreigners to the covenants embodying God's promise. You were in this world without hope and without God. 13 But now, you who were once far off have been brought near through the shedding of the Messiah’s blood.
   14 For he himself is our shalom — he has made us both one and has broken down the m'chitzah which divided us 15 by destroying in his own body the enmity occasioned by the Torah, with its commands set forth in the form of ordinances. He did this in order to create in union with himself from the two groups a single new humanity and thus make shalom, 16 and in order to reconcile to God both in a single body by being executed on a stake as a criminal and thus in himself killing that enmity. 17 Also, when he came, he announced as Good News shalom to you far off and shalom to those nearby, 18 news that through him we both have access in one Spirit to the Father. 19 So then, you are no longer foreigners and strangers. On the contrary, you are fellow-citizens with God's people and members of God's family. (Ephesians 2)

Let’s look at just the most relevant phrases again in isolation:

“You used to be dead … You walked in the ways of the 'olam hazeh  … remember your former state: you Gentiles by birth … You were estranged from the national life of Isra'el. You were foreigners to the covenants embodying God's promise. … you who were once far off have been brought near through the shedding of the Messiah’s blood. … he has made us both one and has broken down the m'chitzah which divided us … He did this in order to create in union with himself from the two groups a single new humanity … both in a single body … through him we both have access in one Spirit to the Father. … you are no longer foreigners and strangers … you are fellow-citizens with God's people and members of God's family.”

It is clear from the Scriptures that non-Jewish individuals who have come to faith in Israel’s Messiah are “no longer foreigners and strangers” but already are “fellow-citizens with God’s people and members of God's family” — that is, they already are full citizens in good standing of the Commonwealth of Israel, exactly the same as those who have been born of Jewish ancestry. It is also clear from biology that no process of “conversion” can change the DNA of a non-Jewish person and make them biologically Jewish.

What purpose, then, can a “conversion” process serve for a non-Jewish citizen of the Commonwealth of Israel other than to deny the Scriptures which clearly say that he/she is already a citizen of that commonwealth? Additionally, biblical Messianic Faith insists that in Messiah there is no difference between Jews and non-Jews. If in truth there is no difference, then what purpose does a “conversion” serve, other than to insist that there is, in fact, a difference! Apparently Rav Sha'ul was not writing under the inspiration of Ruach HaKodesh when he wrote:

For in union with the Messiah, you are all children of God through this trusting faithfulness; because as many of you as were immersed into the Messiah have clothed yourselves with the Messiah, in whom there is neither Jew nor Gentile, neither slave nor freeman, neither male nor female; for in union with the Messiah Yeshua, you are all one. Also, if you belong to the Messiah, you are (present condition, not “you may become”) seed of Avraham and heirs according to the promise. (Gal 3:26-30)

In order to “convert” to Judaism (even to “Messianic” Judaism), the convert must renounce his/her current “religion.” So the Messianic convert must renounce his/her Messianic Faith!

The ultimate question which must be asked is from what is one converting, and to what is that one converting? How can one “convert” from being a citizen of Israel to being a citizen of Israel? To say that one wishes the conversion in order to “become Jewish” is a denial of both the facts of biology and the clear teaching of Scripture. If one is already Messianic in faith, can one “convert” from Messianic Faith to Messianic Faith? Any such attempt at conversion is a clear denial that the m'chitzah (dividing wall) has been broken down. “Conversion” of a non-Jewish Messianic Believer would then, of necessity, be a conversion from Biblical Judaism to Rabbinical Judaism, and the individual should therefore no longer be considered truly “Messianic.”

One argument in favor of providing Messianic Gerut reads:

“All other branches of Judaism provide for Gentile ‘conversion.’ Such seems to demand that Messianic Judaism must also provide for Gentile ‘conversion.’ If not, Messianic Judaism is called into question as a ‘true’ or ‘valid’ Judaism. Also, Messianic Jews normally accept Gentile conversions from other branches of Judaism. If Messianic Judaism does not have its own conversion process, then that means that Gentiles must go (and in fact are encouraged to go) to ‘non-believers’ [i.e., rabbinical, non-Messianic rabbis] as the only path to becoming a Jew. Therefore in practice, other branches of Judaism seem to be more authentic or authoritative than Messianic Judaism. How is it that ‘non-believers’ are considered more authoritative than believers? If conversions by other branches are ‘authentic’ how is it that the Messianic Judaism branch does not perform such? Are we less ‘authentic’ than the others? This perceived impotence by some may be one reason why Messianic Judaism cannot shake itself from being viewed by non-believing Jews as a mis-named sect of Christianity.” [CTOMC.ca]

It would appear that the main thrust of this argument is that the primary reason that Messianic Judaism should provided a “conversion” process is that all the other Jewish “denominations” do, so in order to be accepted as a “true Judaism” by the other Jewish “denominations,” the Messianic community must “get in line,” in spite of the clear teaching of Scripture. All the other Jewish “denominations” reject Yeshua as Mashiach, so perhaps the Messianic community should also reject Him in order to be accepted as “true Judaism?”

The other part of this argument is that if Messianic Judaism doesn’t provide a conversion process, non-Jewish Believers in Messiah will go to non-Messianic rabbis in order to become Jewish. Would it not be a more correct approach to teach non-Jewish Believers what the Bible teaches about them, that they are already “full citizens in good standing” of the Commonwealth of Israel?

The CTOMC argument that is cited immediately above also says:

“… presently no other branch of Judaism will accept a Messianic Jewish conversion. … Aliyah is presently not available to Messianic Jews.”

If no other branch of Judaism accepts Messianic gerut, and aliyah is not available to Messianic Jews, what possible reasons for gerut remains? The CTOMC position provides three additional possible reasons:

1. Unification of a mixed marriage. A married couple might find it to be a unifying help for both of them to be considered Jewish.

2. Unassimilated Jewish ministry. A non-Jewish person called for ministry to the Jews may want to make sure that their work does not think to remove Jews from their Jewishness.

3. Ambiguous Jewish heritage. A person may have strong indications that they have Jewish heritage, but no "proof", so the Gerut serves as a point of assertion and commitment to their Jewish heritage.