The Republic by Plato Part 1 Page 93

And can she or can she not fulfil her own ends when deprived of that excellence?

She cannot.

Then an evil soul must necessarily be an evil ruler and superintendent, and the good soul a good ruler?

Yes, necessarily.

And we have admitted that justice is the excellence of the soul, and injustice the defect of the soul?

That has been admitted.

Then the just soul and the just man will live well, and the unjust man will live ill?

That is what your argument proves.

And he who lives well is blessed and happy, and he who lives ill the reverse of happy?

Certainly.