Does one become a just person by doing acts of justice, or is doing acts of justice the product of being a just person?
First off, clearly both are required. If an wicked person accidently did something that had a beneficial effect, I wouldn't call it a virtuous act. (Or shoud I?) Nonetheless, I think which causes which is important in deciding how to instill values. E.g., if you are going to work at a soup kitchen and your kid doesn't want to go, should you make him? If behaving in a virtuous manner, makes us virtuous, then the answer is yes. If truly virtuous acts require a virtuous heart first, then making him go is no good, and maybe even counterproductive.