Quintilian, Institutio Oratoria, Vol. IV (Loeb)

...but by things themselves. Everything lives and moves, and we receive those new, as if nascent, ideas with favor and concern. We are affected not only by the outcome of the case but also by the danger to the speakers themselves.

17 Beyond these, the voice, graceful and appropriate delivery—adapted as each point requires—is the most powerful tool in speaking and, in short, teaches all things equally. In reading, judgment is more certain, because an audience is often swayed by their own partiality or by the shouts of those applauding. 18 For we are ashamed to disagree, and we are restrained by a sort of silent modesty from trusting our own judgment, even when flawed things please the majority and things that do not deserve approval are praised by a hired claque. 19 But the opposite also happens, that poor judgment fails to show appreciation for what is well said. Reading is free and does not rush past like the momentum of a live speech; one may repeat it as often as desired, whether you are in doubt or wish to fix it deeply in the memory. Let us repeat and reconsider, and just as we swallow food only after it has been chewed and nearly liquefied so that it may be more easily digested, so too reading—not raw, but softened by much repetition and, as it were, prepared—should be committed to memory and imitation.