"So you must not be frightened if a sadness rises up before you larger than any you have ever seen; if a restiveness, like light and cloudshadows, passes over your hands and over all you do. You must think that something is happening with you, that life has not forgotten you, that it holds you in its hand; it will not let you fall. Why do you want to shut out of your life any uneasiness, any miseries, or any depressions? For after all, you do not know what work these conditions are doing inside you.”
― Rainer Maria Rilke, Letters to a Young Poet
The full text of the letter from which this quotation comes.