didactic

instructive (especially excessively)

Fitted or intended to teach; conveying instruction; preceptive; instructive; teaching some moral lesson; as, didactic essays.

from Greek didaktikos, meaning 'able to teach'

“They are largely made up of sober reflections, and appeared to me to require some lively human interest to save them from wearisome didactic dulness.”

— Oliver Wendell Holmes, Complete Project Gutenberg Oliver Wendell Holmes, Sr. Works

“The latter is in substance a more didactic repetition of the former.”