Ortberg writes: Allen Guelzo has written a wonderful book on Abraham Lincoln, and he devotes an entire chapter to the role prudence played in the life of the man who was arguably the most influential leader in the history of America. Guelzo notes that 2,000 years ago prudence was considered one of the greatest of virtues; a hundred years ago it was part of moral philosophy; today it is the punchline of a joke.
Prudence, says Guelzo, was prized by the ancients because it was linked to shrewdness, to excellence in judgment, to the capacity to discern, to the ability to take in a situation and see it in its wholeness. Prudence is foresight and far-sightedness. It's the ability to make immediate decisions on the basis of their longer-range effects.
Prudence is what makes someone a great commodities trader—the capacity to face reality squarely in the eye without allowing emotion or ego to get in the way. It's what is needed by every quarterback or battlefield general. Thomas Aquinas said it was intelligence about "things to be done."