A person of wide experience recently expressed the view that Dag Hammarskjöld’s thought and example are all, so to speak, about ‘the great and good’, and therefore somewhat dull. Too smooth and predictable for our rough times. Is that true? Here we address a "great and good" theme, a platitude of moral discourse: the topic of perseverance. Let’s use it as a test. Is Hammarskjöld’s perspective on the need for perseverance in political processes somehow flat, uninformed or unfreshened by direct experience? Is it just right-thinking ethics or is it knowledge won in action? Does it make the topic larger or smaller? However you may decide, he often returned to the need for perseverance. Doing so, he was speaking to and for himself, to UN colleagues who relied on him, and to the world.
Addressing UN staff members in April 1958, soon after his re-election to a second term as secretary-general, Hammarskjöld said:

If I had any promise…in mind and which I gave to myself five years ago, it was just this one: whatever happens, stick to your guns, so that you can feel satisfaction with what you have done, whatever the outcome. (Public Papers 4, 66)

In earlier entries we have encountered Hammarskjöld’s trusted colleague, the Indian statesman Rajeshwar Dayal. In his autobiographical account of the Congo crisis, in which he played a major role, Dayal recalls a moment with Hammarskjöld at a time—there were so many—when the situation was difficult:

[Hammarskjöld] was in a confident mood and seemed unaffected by the ordeal of the attacks on him at New York. He remarked that principles had a way of asserting themselves, and though we had had our full share, and more, of trials and difficulties, we must firmly adhere to our course. Any concession on principle would be fatal and he felt assured that perseverance, crowned with a little good fortune, would ultimately see us through. (Dayal, Mission, 168, referring to 4 January 1961)

The following pair of statements says much the same: expect setbacks, difficulties, and defeats along worthwhile lines of action, apply dose after dose of perseverance. In the first, Hammarskjöld is reflecting (autumn 1954) about negotiations toward peace in Korea, and looks again at the impact of fear on political processes. In the second, from a talk of 1955 at the University of California–Berkeley, he has in mind averting the threat of nuclear war:

Fear of being misled should never be permitted to mislead us into false positions. With calm and steady faith in the possibility of reaching a final understanding, in spite of all setbacks and difficulties, we shall have the strength and firmness that accepts the setbacks but refuses ever to admit defeat. (Public Papers 2, 198–99) 

We need perseverance, of the kind that equips us not to take defeats to heart, in the knowledge that defeats are unavoidable, and that if our efforts do not seem to get results, it may be because we have not yet applied the necessary degree of perseverance. (
Public Papers 2, 297)

In a commencement address at Amherst College (spring 1955), Hammarskjöld reaches high, no doubt hoping that the graduating class would vividly feel for the world beyond their immediate concerns. His notion here of no final victory is haunting:

This will be no affair of a few months or a few years, of course—a kind of war against fear and hate ending with conclusive victory as the reward of successful effort. Only if we should fail in our faith in human brotherhood might there be something resembling a conclusive end of the struggle—and that would be the destruction of our civilization. No, the signal of success will never be a final victory. It will be found rather in the stamina to continue the struggle, and in the preservation and the strengthening of faith in the future of man. (Public Papers 2, 306)

In the course of a press conference on 4 April 1957, a journalist pressed Hammarskjöld to state a deadline at which he would close off consideration of an issue that had come up in the aftermath of the Suez Crisis. Hammarskjöld would have none of it; all outstanding issues would remain fluid and subject to continuing negotiation:

A question raised by me is never abandoned by me; it is kept alive. (Public Papers 3, 549)