Full Idea
Patience is commended, because a patient person tends to be unperturbed and not carried away by his feelings, but indignant only in the way and on the grounds and for the length of time that his 'logos' prescribes.
Clarification
'Logos' is principle or reason
Gist of Idea
Patient people are indignant, but only appropriately, as their reason prescribes
Source
Aristotle (Nicomachean Ethics [c.334 BCE], 1125b33)
Book Reference
Aristotle: 'Ethics (Nicomachean)', ed/tr. ThomsonJ A K/TredennickH [Penguin 1976], p.160
A Reaction
Because the word 'logos' is used here, this strikes me as Aristotle's best statement of his doctrine of the mean (which is never the middle way, but always the appropriate way).