Why Did Christians Sometimes AVOID Writing?

Early Christians relied on oral tradition since that was the norm in education, not only for them but for all ancient people. There were also many times when Christians intentionally did not write important things down. Is there any evidence that oral tradition is reliable? "Galway" Kevin MacLeod (incompetech.com) Licensed under Creative Commons: By Attribution 4.0 License http://creativecommons.org/licenses/by/4.0/