Book VII · 4

In discourse thou must attend to what is said, and in every movement thou must observe what is doing. And in the one thou shouldst see immediately to what end it refers, but in the other watch carefully what is the thing signified.

In conversation keep abreast of what is being said, and, in every effort, of what is being done. In the latter see from the first to what end it has reference, and in the former be careful to catch the meaning.