Primary source:

https://docsouth.unc.edu/neh/jbrown/jbrown.html

Also see the explanation here, which quotes the specific passage from the primary source:

https://www.reddit.com/r/AntiSlaveryMemes/comments/12azu2l/please_ensure_you_are_not_eating_before_reading/

Guess that explains why I got so many more views and upvotes than normal.

I didn't even know there was a politics stream. I submitted it to History_Memes.

The quote is from a letter written by Vincent Van Gogh on or near April 2, 1883. His original words were in Dutch; for the meme, I gave the translated version.

https://vangoghletters.org/vg/letters/let334/print.html

The other one uses a different template, a Hololive template instead of a Star Wars template. So it's not really the same meme, even if it does have the same text.