M. Tullius Cicero Pro A. Cluentio 51

[51] with what anxiety, O ye immortal gods! with what solicitude of mind! with what fear! Indeed, I am always very nervous when I begin to speak. As often as I rise to speak, so often do I think that I am myself on my trial, not only as to my ability, but also as to my virtue and as to the discharge of my duty; lest I should either seem to have undertaken what I am incapable of performing, which is an impudent act, or not to perform it as well as I can, which is either a perfidious action or a careless one. But that time I was so agitated, that I was afraid of everything. I was afraid, if I said nothing, of being thought utterly devoid of eloquence, and, if I said much in such a case, of being considered the most shameless of men. 19
  I recollected myself after a time, and adopted this resolution, that I must needs act boldly; that the age which I was of at that time generally had much allowance made for it, even if I were to stand by men in danger, though their cause had but little justice in it. And so I acted. I strove and contended by every possible means, I had recourse to every possible expedient, to every imaginable excuse in the case, which I could think of; so as, at all events, (though I am almost ashamed to say it,) no one could think that the cause had been left without an advocate.