From Letters to a Young Poet:

 

Nobody can counsel and help you, nobody. There is only one single way. Go into yourself. Search the reason that bids you write; find out whether it is spreading out its roots in the deepest places of your heart, acknowledge to yourself whether you would die if it were denied you to write. This above all—ask yourself in the stillest hour of your night: Must I write? Delve into yourself for a deep answer. And if this should be affirmative, if you may meet this earnest question with a strong and simple, "I must," then build your life according to this necessity; your life even into its most indifferent and slightest hour must be a sign of this urge and a testimony to it.

 

From The Poet's Guide to Life: The Wisdom of Rilke:

 

... to attach oneself someplace to nature, to that which is strong, striving and bright with unreserved readiness, and then to move forward in one's efforts without calculation or guile, even when engaged with the most trivial and mundane activities. Each time we thus reach out with joy, each time we cast our view toward distances that have not yet been touched, we transform not only the present moment and the one following but also the past within us, weave it into a pattern of our existence, and dissolve the foreign body of pain whose exact composition we ultimately do not know.

 

Books by Rilke at Powell's Books