I have a quote by Dag Hammarskjold beginning "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."

I need to know the specific cite for this including page number.
Thank you for your help.

On Wikiquote under "Markings (1964)" [ Published posthumously in 1963] it lists this quote as a journal entry by Hammarskjold.
http://en.wikiquote.org/wiki/Dag_Hammarskj%C3%B6ld

Also here.