Even within the New Testament (NT) itself, we have evidence that the individual NT documents were copied by hand and that these copies circulated among the churches. In Colossians 4:16, Paul writes, “When this letter has been read among you, have it read also in the church of the Laodiceans; and see that you also read the letter from Laodicea.”
Over time, the early church grouped selections of inspired writings and copied them together. By the mid-second century, the four canonical Gospels and Paul’s letters were apparently grouped and copied as units. Not much later, the entire NT was grouped and copied as a recognized body of inspired writings. The earliest extant canonical list we have of the NT (the Muratorian Canon) has been dated to AD 190.
As early Christians copied, recopied, and copied copies (all by hand), small variations were inevitably introduced into the manuscripts. And, although Church Fathers sometimes speculated about copyist errors or the original reading of manuscripts, it was virtually impossible to codify accurately such discussion until one could reproduce a text without any variation. Thus, after the printing press was introduced to Europe in 1454, possibilities for comparing manuscripts with an unchanging standard arose.