Happiness is secured through virtue; it is a good attained by man's own will.

Thomas Aquinas’s quote suggests that happiness is not something that can be granted or attained through external circumstances, but rather it is secured through virtue and the will of the individual. According to Aquinas, true happiness is a product of living a life of moral integrity, guided by the virtues of wisdom, courage, temperance, and justice. In this view, happiness is achieved by making choices that align with one’s higher moral nature and striving to act according to what is good and right, rather than being dependent on fleeting external pleasures or material gains.

The phrase "a good attained by man's own will" emphasizes the importance of personal agency and responsibility in the pursuit of happiness. Aquinas believes that humans have the freedom to choose their actions and cultivate virtues through their will. Happiness, in this sense, is not passive; it requires effort, discipline, and a conscious decision to live virtuously. By aligning one’s will with moral goodness, a person is able to cultivate a lasting and meaningful happiness that is not subject to the volatility of external circumstances.

Aquinas's view on happiness comes from his broader philosophical and theological framework, which combines Aristotelian ethics with Christian teachings. He argued that human beings are meant to achieve their ultimate purpose through the pursuit of goodness and virtue, which lead to fulfillment and happiness. For Aquinas, happiness is the end goal of human life, and it is reached by living in accordance with both natural law and divine law.

The origin of this quote can be found in Aquinas’s works on ethics and morality, particularly his Summa Theologica, where he discusses the nature of the good life and the importance of virtue in achieving happiness. Aquinas viewed happiness as a state of complete well-being that arises not from the accumulation of external goods, but from the cultivation of moral virtues and the alignment of one’s actions with a higher moral purpose. In this sense, happiness is both a choice and a result of living in harmony with one’s ethical and spiritual values.