"What Is Written with the Quill Can't Be Cut Out with an Axe"

"A word isn't like a sparrow -- if it flies out, you can't catch it."

Two Russian sayings I was reminded of; in the original they are "Что написано пером, не вырубишь топором" (that one rhymes) and "Слово не воробей, вылетит—не поймаешь."