Source, in full
Does not appear attributed to Socrates in any known ancient writings. Earliest source found on google books is p. 123 of John Taylor's 2013 book Chewing The Cud: Alcibiades and Socrates Talk Life, Love and Nietzsche, in an original dialogue written by Taylor. But he may have gotten the line from the internet, where versions of the quote circulated prior to 2013—the earliest appearance located in this article was on a 2006 archive.org snapshot of a personal website.