50% sureLots of sources credit Auguste Rodin with this, and they agree with each other. The book or the speech it first came from hasn't turned up yet.
What turned up
Attributed; earliest located citation is Leonard William Doob, Hesitation: Impulsivity and Reflection (1990), p. 124 — a posthumous compilation, so held at likely.
Work
collected in Hesitation: Impulsivity and Reflection (Leonard William Doob, 1990), p. 124
Occasion
remembered as Rodin's word on the slow, deliberate side of a sculptor's work
Sources checked
en.wikiquote.orgChecked using claude-fable-5, 22 August 2026Wikiquote Attributed section — only citation is Doob 1990, posthumous compilation (Rodin d. 1917). Negative check this pass: NOT in Mauclair 1905, Art 1912, or Cladel 1917 (all fetched in full, grepped). Promotion path: a lifetime French source (Gsell/Coquiot).