POLONIUS: Brevity is the soul of wit.

William Shakespeare (1564–1616) English dramatist and poet

Hamlet, Act 2, sc. 2, l. 97 (2.2.97) (c. 1600)
    (Source)

In full, from the least brief-speaking character in the play:

Therefore, since brevity is the soul of wit,
And tediousness the limbs and outward flourishes,
I will be brief ...."