Institutio Oratoria

The proposition, whether single or multiple, must, on every occasion when it can be employed with profit, be clear and lucid; for what could be more discreditable than that a portion of the speech, whose sole purpose is to prevent obscurity elsewhere, should itself be obscure? Secondly it must be brief and must not be burdened with a single superfluous word; for we are not explaining what we are saying, but what we are going to say.