From friend Fanny Johnson
I expect to pass through this world but once; any good thing therefore I can do, or any kindness that I can show to any fellow creature, let me do it now; let me not defer or neglect it, for I shall not pass this way again.
Researching the origins and authorship of this quote proved quite interesting. It is generally credited to Stephen Grellet, born Ettiene De Grellet du Mabillier (1773 -1855). He was the son of a counselor to King Louis XVI.
During the French Revolution of 1792 he was sentenced to be executed, but in 1795 he escaped and fled to the United States. Impressed by the writings of William Penn and Quaker beliefs, he joined the Society of Friends in 1796 and became involved in missionary work across North America and Europe.
In Cassell's Book of Quotations, published in 1914 by W. Gurney Benham, the author states that every effort to identify the author of this much quoted saying had failed. There seems to be some authority in favor of Stephen Grellet being the author, but the passage does not appear in any of his printed works.
There is nothing like looking, if you want to find something.
You certainly usually find something, if you look,
but it is not always quite the something you were after.
JRR Tolkien