Virtue theory belongs to the Aristotelian ethics, these philosophical ethics answer the question on how humans should best live. Aristoteles believes that to develop excellence you needed virtue and happiness. He believed firmly that virtue is practical and the principal purpose of ethics is to be good and just to only know it.
“Aristotle first used the term ethics to name a field of study developed by his predecessors Socrates and Plato. Philosophical ethics is the attempt to offer a rational response to the question of how humans should best live. Aristotle regarded ethics and politics as two related but separate fields of study, since ethics examines the good of the individual, while politics examines the good of the city-state.
Aristotle’s writings have been read more or less continuously since ancient times, and his ethical treatises, in particular, continue to influence philosophers working today. Aristotle emphasized the importance of developing excellence (virtue) of character (Greek ethikē aretē), as the way to achieve what is finally more important, excellent conduct (Greek energeia). As Aristotle argues in Book II of the Nicomachean Ethics, the man who possesses character excellence does the right thing, at the right time, and in the right way. Bravery and the correct regulation of one’s bodily appetites are examples of character excellence or virtue. So acting bravely and acting temperately are examples of excellent activities. The highest aims are living well and eudaimonia a Greek word often translated as well-being, happiness or “human flourishing”. Like many ethicists, Aristotle regards the excellent activity as pleasurable for the man of virtue. For example, Aristotle thinks that the man whose appetites are in the correct order actually takes pleasure in acting moderately.
Aristotle emphasized that virtue is practical and that the purpose of ethics is to become good, not merely to know. Aristotle also claims that the right course of action depends upon the details of a particular situation, rather than being generated merely by applying a law. The type of wisdom which is required for this is called “prudence” or “practical wisdom” (Greek phronesis), as opposed to the wisdom of a theoretical philosopher (Greek Sophia). But despite the importance of practical decision-making, in the final analysis, the original Aristotelian and Socratic answer to the question of how best to live, at least for the best types of human, was to live the life of philosophy.'” https://en.wikipedia.org/wiki/Aristotelian_ethics