The more you say, the less people remember.
The fewer the words, the greater the profit.

François de Sales (1567-1622) French bishop, saint, writer [a.k.a. Francis de Sales, b. François de Boisy]

(Attributed)

In S.A. Bent, comp., Familiar Short Sayings of Great Men (1887). Usually attributed, due to structure of that reference, to Francois Fénelon.