In part three of “Plato’s” “Meno”, Meno is still wanting to know what virtue is and so he keeps on asking Socrates about how to learn and understand it, so he can have virtue.
Then since we are of one mind as to the duty of inquiring into what one does not know, do you agree to our attempting a joint inquiry into the nature of virtue? [p. 28]
What Meno really wants to know is not what virtue is. Meno wants to know how to get power and be successful and so once again, Socrates makes Meno think again about his question, by asking him one as well.
Then if virtue is something that is in the soul, and must needs be profitable, it ought to be wisdom, seeing that all the properties of the soul are in themselves neither profitable nor harmful, but are made either one or the other by the addiction of wisdom or folly; and hence, by this argument, virtue being profitable must be a sort of wisdom.
In order for Meno to understand, Meno has to stop wanting to understand virtue for the wrong reason, and want to understand for the purpose of being better. The quote is very important because socrates is saying that virtue must be profitable, or a source and this sets him up to be able to question Meno if everything has to be profitable, and thus, getting Meno to think more and more, and break apart everything that he thinks he knows, so that he can be truly sure and so that he can understand and build up a better understanding.