M. Tullius Cicero Pro L. Murena 9

[9] If, indeed, I may rest from my labours,—if you advise me that I can do so,—if no reproach of indolence, none of unworthy arrogance, none of inhumanity is incurred by so doing, in good truth I will willingly rest. But if flying from toil convicts me of laziness,—if rejection of suppliants convicts me of arrogance,—if neglect of my friends is a proof of worthlessness, then, above all others, this cause is such an one as no industrious, or merciful, or obliging man can abandon. And you may easily form your opinion of this matter, O Servius, from your own pursuits. For if you think it necessary to give answers to even the adversaries of your friends when they consult you about law, and if you think it shameful, when you have been retained as an advocate for him in whose cause you have come forward, to fail; be not so unjust; as, when your springs are open even to your enemies, to think it right that our small streams should be closed even against our friends.