From a letter written in 1966 by Thomas Merton to Jim Forrest, which can be found in his book, The Hidden Ground of Love
“Do not depend on the hope of results. When you are doing the sort of work you have taken on, essentially an apostolic work, you may have to face the fact that your work will be apparently worthless and even achieve no result at all, if not perhaps results opposite to what you expect.
As you get used to this idea, you start more and more to concentrate not on the results but on the value, the rightness, the truth of the work itself.
And there too a great deal has to be gone through, as gradually you struggle less and less for an idea and more and more for specific people. The range tends to narrow down, but it gets much more real. In the end, it is the reality of personal relationships that saves everything.”