For nothing can be expedient which is not at the same time morally right; neither can a thing be morally right just because it is expedient, but it is expedient because it is morally right.
 Marcus Tullius Cicero, On Duties (44 BC). copy citation

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Author Marcus Tullius Cicero
Source On Duties
Topic time right
Date 44 BC
Language English
Reference
Note Translated by Walter Miller
Weblink http://www.constitution.org/rom/de_officiis.htm

Context

“But because he thought this not expedient for his country, he believed that it was therefore morally right for him to declare his conviction and to suffer for it. When they argued also that what is highly expedient may prove to be morally right, they ought rather to say not that it "may prove to be" but that it actually is morally right. For nothing can be expedient which is not at the same time morally right; neither can a thing be morally right just because it is expedient, but it is expedient because it is morally right. From the many splendid examples in history therefore, we could not easily point to one either more praiseworthy or more heroic than the conduct of Regulus. {111} XXXI. But of all that is thus praiseworthy in the conduct of Regulus, this one feature above all others calls for our admiration:” source