Full Idea
Even if virtues are many and various, at least they all have some common character which makes them all virtues.
Clarification
'Virtue' here is the Greek word 'areté', which also translates as 'excellence'
Gist of Idea
Even if virtues are many and various, they must have something in common to make them virtues
Source
Plato (Meno [c.376 BCE], 72c)
Book Reference
Plato: 'Protagoras and Meno', ed/tr. Guthrie,W K C [Penguin 1956], p.117