"They will ask: Who gave you the Teaching? Answer: The Mahatma of the East. They will ask: Where does He live? Answer: The abode of the Teacher not only cannot be made known but cannot even be uttered... They will ask: When can I be useful? Answer: From this hour unto eternity. When should I prepare myself for labor?... Lose not an hour! And when will the call come? ...Even sleep vigilantly. How shall I work until this hour?... Enhancing the quality of labor. (preamble)"
January 1, 1970
https://en.wikiquote.org/wiki/Masters_of_Wisdom_(Theosophy)