Modern scholarship is still taking uncommon pains over determining the character and history of the early Christian grouping called Jew- ish-Christianity or Judaeo-Christianity. Besides the New Testament writings, the Christian reworkings of older Jewish legends (apocrypha and pseudepigrapha), and the witness of the church fathers, our sources for understanding of the group are quite limited and complex; they are based on the literature connected with the Pseudo-Clementine writings (Homilies and Recognitions), elements of Theophilus of Antioch, and, the so-called Jewish-Christian gospels known only in fragments: the gospels of the Hebrews, of the Nazoreans, of the Ebionites. The wide variety encountered at all levels of the primitive church is found here as well. Jewish-Christianity seems to have taken a plethora of forms.
It was only step by step that Christianity was identified as a distinct religion by its own members, by the Jewish community, and by the Roman rulers. The Jewish influence on Christianity was obviously seminal in a literal sense and there is a Jewish element to Christianity that is essential and permanent. If almost everything in Christianity could, in that way, be called Jewish-Christian, this communality is certainly not what is meant when reference is made to the precise phenomenon of Jewish-Christianity and to the group of early Christians wearing that name.
It goes without saying that the earliest Christians came from among ethnic and religious Jews. They were Christian Jews or Judean Christians, and here we think first of all of the Jerusalem community gathered around the twelve apostles. The name “Nazarene” or “Nazorean” encountered in Acts 24:5 and in the church fathers sometimes designates those first Jewish believers in Jesus; they somehow survived the destruction of Jerusalem (by fleeing to Pella?) and were found in Palestine and Syria until late in the fourth century according to some, although in decreasing numbers. The New Testament authors were mainly Judean Christians or Christian Jews, that is, Christians of Jewish descent.
Paul was a Christian Jew in this sense. But the first Christians, by the mere fact of their “regular going to the Temple” (Acts 2:46), were not strictly Jewish-Christians. To justify that statement, we must proceed carefully. After Gentiles, mainly thanks to the influence of Paul, were accepted into the church in increasing numbers without being asked to maintain the Mosaic prescriptions (Acts 15), the ethnic Jews who had joined the church were forced to reconsider or relax the binding character of the Jewish practices (circumcision of males, dietary laws, refusal of table-fellowship, Sabbath and festival observance), a development discernible in the Jerusalem community led by James, the brother of the Lord, called the Just, and indeed in Antioch. And here we come closer to the Jewish-Christians proper.
Some Christians, Greek-speaking Gentile converts—some of whom may have been previous proselytes or God-fearers—as well as ethnic Jews, were reluctant to give up Jewish observance; critical of Paul and his letters, they assumed that it was preferable to uphold legal observance along with the church requirements, thus in a way combining the Jewish and the Christian religions. Such is the group properly called Jewish-Christianity, still quite visible within the church around the middle of the second century, distinct from all heretical groups mentioned by Justin and rather considered with tolerance by him. The name does not refer to race anymore, nor does it to thought categories and literary forms borrowed from Judaism and surviving within Christian theology, nor to patterns of worship inherited from the synagogue service. It is only in a general, even improper sense that all those factors can be called Jewish-Christian.
Thus recent research clearly tends to restrict the meaning of the term Jewish-Christianity and to apply it only to the enforced maintenance of Jewish practice among Christians everywhere in the church and not exclusively in the Jerusalem or Palestinian community (e.g., the Ps.-Clementine romance exemplifies Jewish-Christianity although it originates in Greek-speaking Syria).
Jewish-Christians were gradually forced out of the church mainstream. They first split into two branches, so to speak, and became alienated from the church in quite different circumstances. First, Christians who merely wished others to uphold the practice of Jewish law or favored a return to it could be called “Judaizers”; echoes of their activity are found in the New Testament “circumcision party” (Acts 11:2, 15:5) and in Ignatius's letters. They were censored. Second, Christians who not only wished others to keep the law but were intent on compelling all converts to continue with the practice of the law of Moses were called “Ebionites” (the “poor”) by the church fathers from Irenaeus on. They insisted that those who embraced Christianity also embraced Judaism as a fuller way of imitating Jesus, a Jew who had come to fulfill the Jewish law, not to abrogate it. With time, Ebionites became sectarians, seeking not only to preserve or reintroduce Jewish practice but also to add their own theological idiosyncrasies; they ended up propounding views no longer acceptable to the church, for example, that Jesus was prophet or messiah, yet not the son of God, or that he was merely “adopted” as son; they were then labeled heretics.
Still in the third and fourth centuries Judaizers are encountered in the church. They are the Christians, probably Gentiles, whom Origen, Ephrem, and John Chrysostom criticized for their continued flirting with Jewish practices; they were urged to refrain from attending the synagogue on Saturday and the church on Sunday, from sharing Passover meals with Jews and participating in the still highly attractive and popular Jewish festivals. Did they also maintain contacts with rabbis? Possibly. At any event, the church fathers enjoined them to stay away from Jewish practices; they never warned Christians, however, against using the Jewish scriptures or Jewish conceptual categories, expressions, and ideas. Those belonged forever to Christian thought and culture. Jewish-Christianity, as described, receded by the end of the second century in the West and in the fourth century in the East when it became identified as Ebionism. But Jewish practice and ritual remained for many an object of fascination.
In contrast with Jewish-Christian tendencies, a movement developed in the opposite direction in the second century. Perhaps prompted by the excesses of the Bar Kokhba revolt, it wanted a Judaism-free Christianity and reacted to what it took to be an overemphasis on the Jewish element even in the Gentile church. Besides some Gnostic teachers, its main spokesman was Marcion. He not only agreed with Justin that Gentiles had replaced Jews in the covenant with God; he wished to expunge everything Jewish from the Christian church. He rejected the entire Hebrew Bible, retained of the gospels only a mutilated Luke, and extolled the teachings of Paul critical of the law. In his unrealistic grumbling at everything Jewish, Marcion can be compared only with another extremist, Tatian, who vituperated against everything Greek.