Wisdom from the Early Stoics, Zeno of Citium 61

The virtues, the Stoics say, are goods of the nature at once of ends and of means. 

On the one hand, in so far as they cause happiness they are means, and on the other hand, in so far as they make it complete, and so are themselves part of it, they are ends. 

Similarly of evils some are of the nature of ends and some of means, while others are at once both means and ends. 

Your enemy and the harm he does you are means; consternation, abasement, slavery, gloom, despair, excess of grief, and every vicious action are of the nature of ends. 

Vices are evils both as ends and as means, since in so far as they cause misery they are means, but in so far as they make it complete, so that they become part of it, they are ends. 

—Diogenes Laërtius, 7.97 

IMAGE: Jacques du Broeucq, The Cardinal Virtues (c. 1545)