"Brethren, weigh your sermons. Do not retail them by the yard, but deal them out by the pound. Set no store by the quantity of words which you utter, but strive to be esteemed for the quality of your matter. It is foolish to be lavish in words and niggardly in truth." -- Lectures to My Students, p. 77.
"We ought seldom to go much beyond that--forty minutes, or say, three-quarters of an hour. If a fellow cannot say all he has to say in that time, when will he say it?... Brevity is a virtue which is within the reach of all of us; do not let us lose the opportunity of gaining the credit which it brings. If you ask me how I may shorten my sermons, I should say, study them better. Spend more time in the study that you may need less in the pulpit. We are generally longest when we have least to say.A Man with a great deal of well-prepared matter will probably not exceed forty minutes. When he has less to say he will go on for fifty minutes. And when he has absolutely nothing he will need an hour to say it in. Attend in these minor things and it will help to retain [the people's] attention." -- Lectures to My Students, pp. 155, 156