How did ancient Greeks connect virtue with a person’s own well-being?

In ancient Greek philosophy, the connection between virtue and well-being is centered on the concept of eudaimonia, often translated as "human flourishing" or "living well." Rather than a fleeting mood or state of mind, eudaimonia represents the successful achievement of a good life.12

Ancient thinkers linked this flourishing to arete, or "virtue/excellence," which is defined as the disposition that enables a thing to perform its characteristic function well. Just as a knife’s virtue is its ability to cut effectively, human virtue is the set of qualities that enables a human being to live a good life. Because humans are uniquely defined by their capacity to reason, ancient philosophers argued that the highest human good consists of rational activity performed in accordance with virtue.213

For Aristotle, this meant that the life of virtue is inherently rewarding, as it constitutes the fulfillment of human nature. Similarly, in Plato’s Republic, virtue is viewed as the "health" of the soul, where internal harmony allows an individual to function properly and achieve true well-being.32