I really need help in describing and evaluating the answer, that virtue theorists make when answering this question. Can you point me in the right direction? Any help would be appreciated.
Virtue as a philosophical notion goes back to Socrates who famously said that virtue is knowledge and vice is ignorance. What this meant for Socrates was that no one does evil knowingly, in other words, vice is the absence of knowledge. To know the good is to do it. This is why, for Socrates, the real question is not how to live but rather how to live properly or how to live well.
Saying that virtue is knowledge would seem to be wrong as we know that we ourselves and others do what we know to be wrong or evil. Socrates didn't deny that human beings did evil. However, he maintained that they do it believing it is good in some way or that the end justifies the means. For instance the woman who was recently reported to have killed her daughter said she did it because she believed she was possessed ...
For Socrates, to know good is to do good. Evil comes from ignorance. So, in Socratic terms, knowledge is virtue while vice is ignorance. This post discusses what a virtuous behaviour consists of. Does knowledge really equal virtue?