This quote is often attributed to Mark Twain and Benjamin Franklin as well. In one form or another, it actually goes back to Cicero, who I believe is the earliest writer of this idea.
This is all covered in the Quote Investigator link given.
Certainly it is documented as appearing in Pascal's writing, and both Twain and Franklin postdate that.
Certainly if Cicero said it then that would be earlier, but while it is (later than Pascal) attributed to Cicero, there are no writings quoted by Cicero as containing the sentiment.
Again, all this is in the lunk page, so I'd be interested if you could provide an earlier reference.
Do you have a reference to Cicero's writings where he says this?
This appears in his dialogue On Oratory, and the attribution of the modern version of the direct quote to him is a bit of a misattribution because he doesn't say it (ironically) in so few words.
The parent I responded to gave the exact Pascal quote, but it has been given in many forms by many writers, all of whom had likely read quite a bit of Cicero.
Martin Luther also talked the same way about his sermons far earlier than Pascal.
The well-known Shakespeare quote, "Brevity is the soul of wit" is also another (loose) translation of a passage from On Oratory.
Quoting from https://quoteinvestigator.com/2012/04/28/shorter-letter/
"The French statement appeared in a letter in a collection called “Lettres Provinciales” in the year 1657:
"Je n’ai fait celle-ci plus longue que parce que je n’ai pas eu le loisir de la faire plus courte.
"Here is one possible modern day translation of Pascal’s statement. Note that the term “this” refers to the letter itself.
"I have made this longer than usual because I have not had time to make it shorter."