What did didache teach?

The Didache is a pious fraud, one of many circulating at the time that was claimed to be written by the apostles. It contradicts the New Testament and is full of "gross errors". The Didache is responsible for the false trinity baptism formula that can only be found in one other place in The Bible, which is the disputed Matthew 28:19, which does not appear in any early manuscripts before the 4th century. While in 17 other places the Bible says baptism should be done in the name of Jesus and "there is no other Name given by which men can be saved".

The Didache is mentioned by some of the church fathers but was not considered to be a canonical book. The Didache has a lot of strange ideas that are not in the bible. Didache looks more like a Catholic forgery and in that time many false writings have circulated assimilated with big names, to make them look more genuine. It is quoted several times in the Catechism of the Catholic Church. it was written sometime after the death of the last Apostle, John, although some believe it can be dated around 70AD. Dating the document has fallen foul of redaction critics in much the same way as have the canonical texts - thus, older scholarship argued for a mid-second century date.

The story of the "discovery" of the complete text rivals the finding of the Dead Sea Scrolls and Nag Hammadi Library in the early twentieth century. When the fourteenth and fifteenth century Renaissance failed to unearth a single copy of The Didache, scholars grew pessimistic, even skeptical of its authenticity. However, in 1873, a single copy written by the hand of "Leon, the scribe and sinner," dated 1056, including the customary tachygraphic signs and abbreviations of Latin and Greek copyists, was discovered by Archbishop Philotheos BryenniOS in the library of the Greek Convent of the Holy Sepulchre in Istanbul (Constantinople). Some problems encouraged skepticism by the literati: that professional catalogers had already systematically combed through the library and failed to unearth the document; and Constantinople seemed a convenient place to find it. Ten years of fierce debate ended with the first English publication in New York on March 20, 1884. Five thousand copies were sold on the first day alone. Detractors maintained the charge of a "modern forgery" but it is now almost entirely recognized as a genuine text.

A. D. Howell-Smith writes about the Didache (Jesus Not a Myth, p. 120):

The simple Christology of Acts confronts us again in the so-called Teaching of the Apostles, a composite work, of which the first six chapters seem to be a Christian redaction of a Jewish document entitled The Two Ways, while the rest is the work of several Christian writers, the earliest belonging to the first century and the latest perhaps to the fourth. The Jesus mentioned in this book's account of the celebration of the Eucharist is just the "Servant" (Ðáéò) of God, who has made known the "holy vine" of God's "Servant" David; nothing is said of the bread and wine being the body and blood of Jesus. The formula of baptism in the name of the Trinity, which is given in Chap. VII, must come from a later hand, though possibly earlier than Justin Martyr, who is familiar with it.

All later church father apostasy based on the triune formula can be traced back to the Didache.