Several minutes after writing the last post I found this in a book of collected prayers*:
"I don't know who - or what - put the question, I don't know when it was put. I don't even remember answering. But at some moment I did answer Yes to Someone - or Something - and from that hour I was certain that existence is meaningful and that, therefore, my life in self-surrender had a goal. From that moment I have known what it means 'not to look back,' and 'to take no thought for the morrow.'"
* The Oxford Book of Prayer, George Appleton, Ed., 1985