Once again we are drawn to see the face of Christ reflected in the writings of the early Christians. The ancient document titled in English, The Teaching of the (Twelve) Apostles is regarded by modern scholars as a late first/early second century 'church manual' which was used to prepare catechumens for baptism and to pass on the primitive traditions about church order. The modern consensus is that the title was added later, so the work is typically referred to as The Didache which is Greek for 'Teaching.' In the first Christian centuries this work was highly esteemed. The document may have been regarded as Scripture by Clement of Alexandria in the second century and Origen in the third century. By the fourth century the Didache was excluded from the canon of Scripture, though it is still recommended for reading by St Athanasius and Didymus the Blind. Sections of the Didache were incorporated in later "Church Orders."
Modern studies have suggested that this work is a composite document which was edited between 70 -110 A.D. It is likely that two short sections of the Didache were used by the early Church to train catechumens who were being prepared for baptism. There is a section on good and evil behavior entitled 'the Two Ways' (1:1-6:2) and a section containing ancient liturgical traditions found in 6:3-10:6. This material is roughly contemporary with St. Mark's Gospel. Scholars believe that the 'Two Ways' section may have existed as an earlier independent document in the Jewish world. The editor then added certain sayings of Jesus, most likely from Matthew's Gospel. Other material concerning the behavior of traveling missionary apostles, and prophets and of the leaders of the community were then added near the close of the first century.
The original Jewish 'Two Ways' tradition focused on the teachings of the ten commandments, "There are two ways, one of life, the other of death, and between the two ways there is a great difference." (Didache 1:1). The Christian version of this tradition found in the Didache replaces the authority of the law with that of the sayings of Jesus. One interesting note in this section of the document occurs after quoting the fifth and sixth commandments, "You shall not murder; you shall not commit adultery." The Didache includes an example after this prohibition, "you shall not abort a child or commit infanticide." Both the Old Testament and Jewish custom recognized the grave offence of this act, but this is the first explicit instance of a Christian prohibition against this intrinsically evil act (Cf. Evangelium Vitae 62).
The later section of the Didache (Chapters 7-15) deals with variety of topics. The Didache gives instruction on how to perform Baptism, on the Eucharist, and even how to deal with traveling apostles and prophets. The section on Baptism advises;
"Now concerning baptism, baptize as follows: after you have reviewed all these things, baptize "in the name of the Father and of the Son and of the Holy Spirit"in running water [literally "living water"]. But if you have no running water, then baptize in some other water; and if you are not able to baptize in cold water, then do so in warm. But if you have neither, then pour water on the head three times "in the name of Father and Son and Holy Spirit" (Didache 7:1-3).The words; "after you have reviewed all these things" (Didache 7:1) refer to the catechesis in the 'Two Ways' document. The baptismal advice of the Didache parallels the requirements found in the rabbinic traditions recorded in the Mishnah in the early second century. The Mishnah, (Mikwaot 1:1-8) distinguishes six grades of water with two criteria: "living" water is ranked above "drawn" water, and cold above hot. The Didache expresses preferences similar to rabbinic traditions but is more flexible.
Proselyte baptism also played a role in role in Gentile conversions to Judaism. Later Talmudic traditions view the newly baptized proselyte "like a child newly born" (Babylonian Talmud, Yevamoth 48b) with a completely new legal identity and understood that "God forgives the proselyte all his sins" through the conversion rite (Talmud Yerushalmi, Bikkurim 3:3). There is even evidence of a first century rabbinic dispute between Eliezer ben Hyrkan (ca. A.D. 90) and Jehoshua ben Chananja over whether circumcision or immersion made a man a Jew. As Pope Benedict has pointed out, already at the time of Jesus, John the Baptist was administering baptism "as a concrete enactment of conversion that gives the whole of life a new direction forever" (Jesus of Nazareth). Later Jesus will baptize with the Holy Spirit creating a new sacramental dimension to this rite. In the Didache, Baptism takes place in the name of the Trinity and implies incorporation into the Eucharistic community which has been "gathered together and became one" (Didache 9:4) in the Eucharist. The newly baptized are invited to join in the Eucharist celebration. The privilege of receiving the Eucharist is denied to those who are not yet baptized;
"But let no one eat or drink of your Eucharist except those who have been baptized into the name of the Lord, for the Lord has also spoken concerning this: 'Do not give what is holy to dogs.'" (Didache 9:5).
Once again we can see the organic development of our Church traditions. Aspects of our modern Rite of Christian Initiation for Adults (RCIA) are already highlighted here in the first century.