95% sureThese words were traced back to where they first appeared. That source is listed below.
What turned up
Divinity College Address (1838).
Sources checked
en.wikiquote.orgChecked using claude-sonnet-5, 20 August 2026Sourced to Divinity College Address, 1838
gutenberg.orgChecked using claude-fable-5, 21 August 2026Divinity School Address (1838), in Miscellanies — exact sentence in primary text on Project Gutenberg ('Imitation cannot go above its model. The imitator dooms himself to hopeless mediocrity.')