A task becomes a duty from the moment you suspect it to be an essential part of that integrity which alone entitles a man to assume responsibility.

Dag Hammarskjöld (1905–1961), the second Secretary-General of the United Nations, kept a private spiritual and philosophical journal alongside his public life in diplomacy. The line reflects the ethical rigor that marked his approach to international service: responsibility is not merely conferred by office but earned through inner integrity. Hammarskjöld often framed leadership as a moral vocation, emphasizing conscience, self-scrutiny, and the willingness to accept burdens once one recognizes them as necessary to one’s wholeness. The quote is consistent with the reflective, aphoristic style of his posthumously published journal, which records meditations on duty, humility, and the costs of public responsibility.

Hammarskjöld draws a sharp line between optional work (“a task”) and moral obligation (“a duty”). The turning point is not external command but an inward recognition: once you sense that doing something is essential to your integrity—your coherence as an honest person—you are bound to it. He also reverses a common assumption about authority: responsibility is not a right that comes with position; it is something one is “entitled” to assume only when grounded in integrity. The quote therefore links ethical self-knowledge to public action, suggesting that genuine leadership begins when conscience converts possibility into obligation.