That's not a Greek proverb. It was written in 1951 by Elton Trueblood, a Quaker, in his book The Life We Prize: https://www.roger-pearse.com/weblog/2017/08/26

That's not a Greek proverb. It was written in 1951 by Elton Trueblood, a Quaker, in his book The Life We Prize: https://www.roger-pearse.com/weblog/2017/08/26/a-society-grows-great-when-old-men-plant-trees-in-whose-shade-they-know-they-shall-never-sit-an-ancient-greek-proverb/comment-page-1/ https://www.roger-pearse.com/weblog/2017/08/26/a-society-gro... The book is available to loan from the Internet Archive: https://archive.org/details/lifeweprize00true https://archive.org/details/lifeweprize00true