Source, in full
From Plutarch, Lives, Pericles, sec. 18. See also the following source provided by the "1000 Quotes Project": Plutarch. Plutarch’s Lives, Vol 3. Translated by Bernadotte Perrin. The Macmillan Co: New York. 1916. Pg 59 or 60. Archived from the original on November 10, 2022. The aforementioned source is available online as The Parallel Lives by Plutarch published in Vol. III of the Loeb Classical Library edition, 1916.