It’s not a quotation, just a paraphrase of Aeschylus by a twentieth century writer , Edith Hamilton, whom many classicists treat with contempt. In the Greek the “wisdom” is just learning (mathos), learning a lesson, learning to accept what life brings, learning what loss feels like. And “in our despair” is just pathos, suffering, experiencing things over which we have no control. But the words ring true, now, as they did on that evening in Indianapolis when Martin Luther King was shot and Kennedy spoke ex tempore in a slum close to going up in flames, saying,
“What we need in the United States is not division; what we need in the United States is not hatred; what we need in the United States is not violence or lawlessness; but love and wisdom, and compassion toward one another, and a feeling of justice toward those who still suffer within our country, whether they be white r they be black. … Let us dedicate ourselves to what the Greeks wrote so many years ago: to tame the savageness of man and to make gentle the life of this world.”
Evan Thomas Robert Kennedy. (pp. 366 f.)
The words rang true then; they still do.